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-rw-r--r--Documentation/RCU/trace.txt5
-rw-r--r--include/linux/llist.h37
-rw-r--r--include/linux/rcupdate.h12
-rw-r--r--include/linux/rcutiny.h6
-rw-r--r--include/linux/srcu.h10
-rw-r--r--include/trace/events/rcu.h10
-rw-r--r--init/Kconfig14
-rw-r--r--kernel/locking/lockdep.c12
-rw-r--r--kernel/locking/locktorture.c6
-rw-r--r--kernel/membarrier.c4
-rw-r--r--kernel/rcu/rcutorture.c19
-rw-r--r--kernel/rcu/srcu.c143
-rw-r--r--kernel/rcu/tiny.c2
-rw-r--r--kernel/rcu/tree.c262
-rw-r--r--kernel/rcu/tree.h15
-rw-r--r--kernel/rcu/tree_exp.h38
-rw-r--r--kernel/rcu/tree_plugin.h7
-rw-r--r--kernel/rcu/tree_trace.c5
-rw-r--r--kernel/rcu/update.c6
-rw-r--r--lib/Kconfig.debug1
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/CFcommon3
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TINY011
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TINY023
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE013
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE024
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE033
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE044
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE053
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE063
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE073
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/TREE084
-rw-r--r--tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt33
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/.gitignore1
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/Makefile16
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/delay.h0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/export.h0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/mutex.h0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/percpu.h0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/preempt.h0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/rcupdate.h0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/sched.h0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/smp.h0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/workqueue.h0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/uapi/linux/types.h0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/.gitignore1
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/kconfig.h1
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/types.h155
-rwxr-xr-xtools/testing/selftests/rcutorture/formal/srcu-cbmc/modify_srcu.awk375
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/assume.h16
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/barriers.h41
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/bug_on.h13
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/combined_source.c13
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/config.h27
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/include_srcu.c31
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/int_typedefs.h33
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/locks.h220
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/misc.c11
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/misc.h58
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/percpu.h92
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.c78
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.h58
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/simple_sync_srcu.c50
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/workqueues.h102
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/.gitignore1
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/Makefile11
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/assert_end.fail1
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force.fail1
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force2.fail1
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force3.fail1
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/main.pass0
-rw-r--r--tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/test.c72
-rwxr-xr-xtools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/test_script.sh102
72 files changed, 2005 insertions, 258 deletions
diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt
index 00a3a38b375a..6549012033f9 100644
--- a/Documentation/RCU/trace.txt
+++ b/Documentation/RCU/trace.txt
@@ -237,7 +237,7 @@ o "ktl" is the low-order 16 bits (in hexadecimal) of the count of
The output of "cat rcu/rcu_preempt/rcuexp" looks as follows:
-s=21872 wd1=0 wd2=0 wd3=5 n=0 enq=0 sc=21872
+s=21872 wd1=0 wd2=0 wd3=5 enq=0 sc=21872
These fields are as follows:
@@ -249,9 +249,6 @@ o "wd1", "wd2", and "wd3" are the number of times that an attempt
completed an expedited grace period that satisfies the attempted
request. "Our work is done."
-o "n" is number of times that a concurrent CPU-hotplug operation
- forced a fallback to a normal grace period.
-
o "enq" is the number of quiescent states still outstanding.
o "sc" is the number of times that the attempt to start a
diff --git a/include/linux/llist.h b/include/linux/llist.h
index fd4ca0b4fe0f..171baa90f6f6 100644
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -3,28 +3,33 @@
/*
* Lock-less NULL terminated single linked list
*
- * If there are multiple producers and multiple consumers, llist_add
- * can be used in producers and llist_del_all can be used in
- * consumers. They can work simultaneously without lock. But
- * llist_del_first can not be used here. Because llist_del_first
- * depends on list->first->next does not changed if list->first is not
- * changed during its operation, but llist_del_first, llist_add,
- * llist_add (or llist_del_all, llist_add, llist_add) sequence in
- * another consumer may violate that.
- *
- * If there are multiple producers and one consumer, llist_add can be
- * used in producers and llist_del_all or llist_del_first can be used
- * in the consumer.
- *
- * This can be summarized as follow:
+ * Cases where locking is not needed:
+ * If there are multiple producers and multiple consumers, llist_add can be
+ * used in producers and llist_del_all can be used in consumers simultaneously
+ * without locking. Also a single consumer can use llist_del_first while
+ * multiple producers simultaneously use llist_add, without any locking.
+ *
+ * Cases where locking is needed:
+ * If we have multiple consumers with llist_del_first used in one consumer, and
+ * llist_del_first or llist_del_all used in other consumers, then a lock is
+ * needed. This is because llist_del_first depends on list->first->next not
+ * changing, but without lock protection, there's no way to be sure about that
+ * if a preemption happens in the middle of the delete operation and on being
+ * preempted back, the list->first is the same as before causing the cmpxchg in
+ * llist_del_first to succeed. For example, while a llist_del_first operation
+ * is in progress in one consumer, then a llist_del_first, llist_add,
+ * llist_add (or llist_del_all, llist_add, llist_add) sequence in another
+ * consumer may cause violations.
+ *
+ * This can be summarized as follows:
*
* | add | del_first | del_all
* add | - | - | -
* del_first | | L | L
* del_all | | | -
*
- * Where "-" stands for no lock is needed, while "L" stands for lock
- * is needed.
+ * Where, a particular row's operation can happen concurrently with a column's
+ * operation, with "-" being no lock needed, while "L" being lock is needed.
*
* The list entries deleted via llist_del_all can be traversed with
* traversing function such as llist_for_each etc. But the list
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 01f71e1d2e94..6ade6a52d9d4 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -1161,5 +1161,17 @@ do { \
ftrace_dump(oops_dump_mode); \
} while (0)
+/*
+ * Place this after a lock-acquisition primitive to guarantee that
+ * an UNLOCK+LOCK pair acts as a full barrier. This guarantee applies
+ * if the UNLOCK and LOCK are executed by the same CPU or if the
+ * UNLOCK and LOCK operate on the same lock variable.
+ */
+#ifdef CONFIG_PPC
+#define smp_mb__after_unlock_lock() smp_mb() /* Full ordering for lock. */
+#else /* #ifdef CONFIG_PPC */
+#define smp_mb__after_unlock_lock() do { } while (0)
+#endif /* #else #ifdef CONFIG_PPC */
+
#endif /* __LINUX_RCUPDATE_H */
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index ac81e4063b40..4f9b2fa2173d 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -27,6 +27,12 @@
#include <linux/cache.h>
+struct rcu_dynticks;
+static inline int rcu_dynticks_snap(struct rcu_dynticks *rdtp)
+{
+ return 0;
+}
+
static inline unsigned long get_state_synchronize_rcu(void)
{
return 0;
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index dc8eb63c6568..a598cf3ac70c 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -33,9 +33,9 @@
#include <linux/rcupdate.h>
#include <linux/workqueue.h>
-struct srcu_struct_array {
- unsigned long c[2];
- unsigned long seq[2];
+struct srcu_array {
+ unsigned long lock_count[2];
+ unsigned long unlock_count[2];
};
struct rcu_batch {
@@ -46,7 +46,7 @@ struct rcu_batch {
struct srcu_struct {
unsigned long completed;
- struct srcu_struct_array __percpu *per_cpu_ref;
+ struct srcu_array __percpu *per_cpu_ref;
spinlock_t queue_lock; /* protect ->batch_queue, ->running */
bool running;
/* callbacks just queued */
@@ -118,7 +118,7 @@ void process_srcu(struct work_struct *work);
* See include/linux/percpu-defs.h for the rules on per-CPU variables.
*/
#define __DEFINE_SRCU(name, is_static) \
- static DEFINE_PER_CPU(struct srcu_struct_array, name##_srcu_array);\
+ static DEFINE_PER_CPU(struct srcu_array, name##_srcu_array);\
is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name)
#define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */)
#define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static)
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 9d4f9b3a2b7b..e3facb356838 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -385,11 +385,11 @@ TRACE_EVENT(rcu_quiescent_state_report,
/*
* Tracepoint for quiescent states detected by force_quiescent_state().
- * These trace events include the type of RCU, the grace-period number
- * that was blocked by the CPU, the CPU itself, and the type of quiescent
- * state, which can be "dti" for dyntick-idle mode, "ofl" for CPU offline,
- * or "kick" when kicking a CPU that has been in dyntick-idle mode for
- * too long.
+ * These trace events include the type of RCU, the grace-period number that
+ * was blocked by the CPU, the CPU itself, and the type of quiescent state,
+ * which can be "dti" for dyntick-idle mode, "ofl" for CPU offline, "kick"
+ * when kicking a CPU that has been in dyntick-idle mode for too long, or
+ * "rqc" if the CPU got a quiescent state via its rcu_qs_ctr.
*/
TRACE_EVENT(rcu_fqs,
diff --git a/init/Kconfig b/init/Kconfig
index 223b734abccd..d0caacb4bc14 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -529,7 +529,6 @@ config SRCU
config TASKS_RCU
bool
default n
- depends on !UML
select SRCU
help
This option enables a task-based RCU implementation that uses
@@ -781,19 +780,6 @@ config RCU_NOCB_CPU_ALL
endchoice
-config RCU_EXPEDITE_BOOT
- bool
- default n
- help
- This option enables expedited grace periods at boot time,
- as if rcu_expedite_gp() had been invoked early in boot.
- The corresponding rcu_unexpedite_gp() is invoked from
- rcu_end_inkernel_boot(), which is intended to be invoked
- at the end of the kernel-only boot sequence, just before
- init is exec'ed.
-
- Accept the default if unsure.
-
endmenu # "RCU Subsystem"
config BUILD_BIN2C
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 7c38f8f3d97b..d9a698e8458f 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4412,13 +4412,13 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
/* Note: the following can be executed concurrently, so be careful. */
printk("\n");
- printk("===============================\n");
- printk("[ INFO: suspicious RCU usage. ]\n");
+ pr_err("===============================\n");
+ pr_err("[ ERR: suspicious RCU usage. ]\n");
print_kernel_ident();
- printk("-------------------------------\n");
- printk("%s:%d %s!\n", file, line, s);
- printk("\nother info that might help us debug this:\n\n");
- printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
+ pr_err("-------------------------------\n");
+ pr_err("%s:%d %s!\n", file, line, s);
+ pr_err("\nother info that might help us debug this:\n\n");
+ pr_err("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
!rcu_lockdep_current_cpu_online()
? "RCU used illegally from offline CPU!\n"
: !rcu_is_watching()
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index f8c5af52a131..d3de04b12f8c 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -780,6 +780,10 @@ static void lock_torture_cleanup(void)
else
lock_torture_print_module_parms(cxt.cur_ops,
"End of test: SUCCESS");
+
+ kfree(cxt.lwsa);
+ kfree(cxt.lrsa);
+
end:
torture_cleanup_end();
}
@@ -924,6 +928,8 @@ static int __init lock_torture_init(void)
GFP_KERNEL);
if (reader_tasks == NULL) {
VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
+ kfree(writer_tasks);
+ writer_tasks = NULL;
firsterr = -ENOMEM;
goto unwind;
}
diff --git a/kernel/membarrier.c b/kernel/membarrier.c
index 536c727a56e9..9f9284f37f8d 100644
--- a/kernel/membarrier.c
+++ b/kernel/membarrier.c
@@ -16,6 +16,7 @@
#include <linux/syscalls.h>
#include <linux/membarrier.h>
+#include <linux/tick.h>
/*
* Bitmask made from a "or" of all commands within enum membarrier_cmd,
@@ -51,6 +52,9 @@
*/
SYSCALL_DEFINE2(membarrier, int, cmd, int, flags)
{
+ /* MEMBARRIER_CMD_SHARED is not compatible with nohz_full. */
+ if (tick_nohz_full_enabled())
+ return -ENOSYS;
if (unlikely(flags))
return -EINVAL;
switch (cmd) {
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 87c51225ceec..d81345be730e 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -564,10 +564,25 @@ static void srcu_torture_stats(void)
pr_alert("%s%s per-CPU(idx=%d):",
torture_type, TORTURE_FLAG, idx);
for_each_possible_cpu(cpu) {
+ unsigned long l0, l1;
+ unsigned long u0, u1;
long c0, c1;
+ struct srcu_array *counts = per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu);
- c0 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[!idx];
- c1 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[idx];
+ u0 = counts->unlock_count[!idx];
+ u1 = counts->unlock_count[idx];
+
+ /*
+ * Make sure that a lock is always counted if the corresponding
+ * unlock is counted.
+ */
+ smp_rmb();
+
+ l0 = counts->lock_count[!idx];
+ l1 = counts->lock_count[idx];
+
+ c0 = l0 - u0;
+ c1 = l1 - u1;
pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
}
pr_cont("\n");
diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c
index 9b9cdd549caa..e773129c8b08 100644
--- a/kernel/rcu/srcu.c
+++ b/kernel/rcu/srcu.c
@@ -106,7 +106,7 @@ static int init_srcu_struct_fields(struct srcu_struct *sp)
rcu_batch_init(&sp->batch_check1);
rcu_batch_init(&sp->batch_done);
INIT_DELAYED_WORK(&sp->work, process_srcu);
- sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array);
+ sp->per_cpu_ref = alloc_percpu(struct srcu_array);
return sp->per_cpu_ref ? 0 : -ENOMEM;
}
@@ -141,114 +141,77 @@ EXPORT_SYMBOL_GPL(init_srcu_struct);
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
/*
- * Returns approximate total of the readers' ->seq[] values for the
+ * Returns approximate total of the readers' ->lock_count[] values for the
* rank of per-CPU counters specified by idx.
*/
-static unsigned long srcu_readers_seq_idx(struct srcu_struct *sp, int idx)
+static unsigned long srcu_readers_lock_idx(struct srcu_struct *sp, int idx)
{
int cpu;
unsigned long sum = 0;
- unsigned long t;
for_each_possible_cpu(cpu) {
- t = READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->seq[idx]);
- sum += t;
+ struct srcu_array *cpuc = per_cpu_ptr(sp->per_cpu_ref, cpu);
+
+ sum += READ_ONCE(cpuc->lock_count[idx]);
}
return sum;
}
/*
- * Returns approximate number of readers active on the specified rank
- * of the per-CPU ->c[] counters.
+ * Returns approximate total of the readers' ->unlock_count[] values for the
+ * rank of per-CPU counters specified by idx.
*/
-static unsigned long srcu_readers_active_idx(struct srcu_struct *sp, int idx)
+static unsigned long srcu_readers_unlock_idx(struct srcu_struct *sp, int idx)
{
int cpu;
unsigned long sum = 0;
- unsigned long t;
for_each_possible_cpu(cpu) {
- t = READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[idx]);
- sum += t;
+ struct srcu_array *cpuc = per_cpu_ptr(sp->per_cpu_ref, cpu);
+
+ sum += READ_ONCE(cpuc->unlock_count[idx]);
}
return sum;
}
/*
* Return true if the number of pre-existing readers is determined to
- * be stably zero. An example unstable zero can occur if the call
- * to srcu_readers_active_idx() misses an __srcu_read_lock() increment,
- * but due to task migration, sees the corresponding __srcu_read_unlock()
- * decrement. This can happen because srcu_readers_active_idx() takes
- * time to sum the array, and might in fact be interrupted or preempted
- * partway through the summation.
+ * be zero.
*/
static bool srcu_readers_active_idx_check(struct srcu_struct *sp, int idx)
{
- unsigned long seq;
+ unsigned long unlocks;
- seq = srcu_readers_seq_idx(sp, idx);
+ unlocks = srcu_readers_unlock_idx(sp, idx);
/*
- * The following smp_mb() A pairs with the smp_mb() B located in
- * __srcu_read_lock(). This pairing ensures that if an
- * __srcu_read_lock() increments its counter after the summation
- * in srcu_readers_active_idx(), then the corresponding SRCU read-side
- * critical section will see any changes made prior to the start
- * of the current SRCU grace period.
+ * Make sure that a lock is always counted if the corresponding unlock
+ * is counted. Needs to be a smp_mb() as the read side may contain a
+ * read from a variable that is written to before the synchronize_srcu()
+ * in the write side. In this case smp_mb()s A and B act like the store
+ * buffering pattern.
*
- * Also, if the above call to srcu_readers_seq_idx() saw the
- * increment of ->seq[], then the call to srcu_readers_active_idx()
- * must see the increment of ->c[].
+ * This smp_mb() also pairs with smp_mb() C to prevent accesses after the
+ * synchronize_srcu() from being executed before the grace period ends.
*/
smp_mb(); /* A */
/*
- * Note that srcu_readers_active_idx() can incorrectly return
- * zero even though there is a pre-existing reader throughout.
- * To see this, suppose that task A is in a very long SRCU
- * read-side critical section that started on CPU 0, and that
- * no other reader exists, so that the sum of the counters
- * is equal to one. Then suppose that task B starts executing
- * srcu_readers_active_idx(), summing up to CPU 1, and then that
- * task C starts reading on CPU 0, so that its increment is not
- * summed, but finishes reading on CPU 2, so that its decrement
- * -is- summed. Then when task B completes its sum, it will
- * incorrectly get zero, despite the fact that task A has been
- * in its SRCU read-side critical section the whole time.
- *
- * We therefore do a validation step should srcu_readers_active_idx()
- * return zero.
- */
- if (srcu_readers_active_idx(sp, idx) != 0)
- return false;
-
- /*
- * The remainder of this function is the validation step.
- * The following smp_mb() D pairs with the smp_mb() C in
- * __srcu_read_unlock(). If the __srcu_read_unlock() was seen
- * by srcu_readers_active_idx() above, then any destructive
- * operation performed after the grace period will happen after
- * the corresponding SRCU read-side critical section.
+ * If the locks are the same as the unlocks, then there must have
+ * been no readers on this index at some time in between. This does not
+ * mean that there are no more readers, as one could have read the
+ * current index but not have incremented the lock counter yet.
*
- * Note that there can be at most NR_CPUS worth of readers using
- * the old index, which is not enough to overflow even a 32-bit
- * integer. (Yes, this does mean that systems having more than
- * a billion or so CPUs need to be 64-bit systems.) Therefore,
- * the sum of the ->seq[] counters cannot possibly overflow.
- * Therefore, the only way that the return values of the two
- * calls to srcu_readers_seq_idx() can be equal is if there were
- * no increments of the corresponding rank of ->seq[] counts
- * in the interim. But the missed-increment scenario laid out
- * above includes an increment of the ->seq[] counter by
- * the corresponding __srcu_read_lock(). Therefore, if this
- * scenario occurs, the return values from the two calls to
- * srcu_readers_seq_idx() will differ, and thus the validation
- * step below suffices.
+ * Possible bug: There is no guarantee that there haven't been ULONG_MAX
+ * increments of ->lock_count[] since the unlocks were counted, meaning
+ * that this could return true even if there are still active readers.
+ * Since there are no memory barriers around srcu_flip(), the CPU is not
+ * required to increment ->completed before running
+ * srcu_readers_unlock_idx(), which means that there could be an
+ * arbitrarily large number of critical sections that execute after
+ * srcu_readers_unlock_idx() but use the old value of ->completed.
*/
- smp_mb(); /* D */
-
- return srcu_readers_seq_idx(sp, idx) == seq;
+ return srcu_readers_lock_idx(sp, idx) == unlocks;
}
/**
@@ -266,8 +229,12 @@ static bool srcu_readers_active(struct srcu_struct *sp)
unsigned long sum = 0;
for_each_possible_cpu(cpu) {
- sum += READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[0]);
- sum += READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[1]);
+ struct srcu_array *cpuc = per_cpu_ptr(sp->per_cpu_ref, cpu);
+
+ sum += READ_ONCE(cpuc->lock_count[0]);
+ sum += READ_ONCE(cpuc->lock_count[1]);
+ sum -= READ_ONCE(cpuc->unlock_count[0]);
+ sum -= READ_ONCE(cpuc->unlock_count[1]);
}
return sum;
}
@@ -298,9 +265,8 @@ int __srcu_read_lock(struct srcu_struct *sp)
int idx;
idx = READ_ONCE(sp->completed) & 0x1;
- __this_cpu_inc(sp->per_cpu_ref->c[idx]);
+ __this_cpu_inc(sp->per_cpu_ref->lock_count[idx]);
smp_mb(); /* B */ /* Avoid leaking the critical section. */
- __this_cpu_inc(sp->per_cpu_ref->seq[idx]);
return idx;
}
EXPORT_SYMBOL_GPL(__srcu_read_lock);
@@ -314,7 +280,7 @@ EXPORT_SYMBOL_GPL(__srcu_read_lock);
void __srcu_read_unlock(struct srcu_struct *sp, int idx)
{
smp_mb(); /* C */ /* Avoid leaking the critical section. */
- this_cpu_dec(sp->per_cpu_ref->c[idx]);
+ this_cpu_inc(sp->per_cpu_ref->unlock_count[idx]);
}
EXPORT_SYMBOL_GPL(__srcu_read_unlock);
@@ -349,12 +315,21 @@ static bool try_check_zero(struct srcu_struct *sp, int idx, int trycount)
/*
* Increment the ->completed counter so that future SRCU readers will
- * use the other rank of the ->c[] and ->seq[] arrays. This allows
+ * use the other rank of the ->(un)lock_count[] arrays. This allows
* us to wait for pre-existing readers in a starvation-free manner.
*/
static void srcu_flip(struct srcu_struct *sp)
{
- sp->completed++;
+ WRITE_ONCE(sp->completed, sp->completed + 1);
+
+ /*
+ * Ensure that if the updater misses an __srcu_read_unlock()
+ * increment, that task's next __srcu_read_lock() will see the
+ * above counter update. Note that both this memory barrier
+ * and the one in srcu_readers_active_idx_check() provide the
+ * guarantee for __srcu_read_lock().
+ */
+ smp_mb(); /* D */ /* Pairs with C. */
}
/*
@@ -392,6 +367,7 @@ void call_srcu(struct srcu_struct *sp, struct rcu_head *head,
head->next = NULL;
head->func = func;
spin_lock_irqsave(&sp->queue_lock, flags);
+ smp_mb__after_unlock_lock(); /* Caller's prior accesses before GP. */
rcu_batch_queue(&sp->batch_queue, head);
if (!sp->running) {
sp->running = true;
@@ -425,6 +401,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount)
head->next = NULL;
head->func = wakeme_after_rcu;
spin_lock_irq(&sp->queue_lock);
+ smp_mb__after_unlock_lock(); /* Caller's prior accesses before GP. */
if (!sp->running) {
/* steal the processing owner */
sp->running = true;
@@ -444,8 +421,11 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount)
spin_unlock_irq(&sp->queue_lock);
}
- if (!done)
+ if (!done) {
wait_for_completion(&rcu.completion);
+ smp_mb(); /* Caller's later accesses after GP. */
+ }
+
}
/**
@@ -613,7 +593,8 @@ static void srcu_advance_batches(struct srcu_struct *sp, int trycount)
/*
* Invoke a limited number of SRCU callbacks that have passed through
* their grace period. If there are more to do, SRCU will reschedule
- * the workqueue.
+ * the workqueue. Note that needed memory barriers have been executed
+ * in this task's context by srcu_readers_active_idx_check().
*/
static void srcu_invoke_callbacks(struct srcu_struct *sp)
{
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index b23a4d076f3d..fa6a48d3917b 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -41,8 +41,6 @@
/* Forward declarations for tiny_plugin.h. */
struct rcu_ctrlblk;
-static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp);
-static void rcu_process_callbacks(struct softirq_action *unused);
static void __call_rcu(struct rcu_head *head,
rcu_callback_t func,
struct rcu_ctrlblk *rcp);
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index cb4e2056ccf3..d80e0d2f68c6 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -281,6 +281,116 @@ static DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
#endif /* #ifdef CONFIG_NO_HZ_FULL_SYSIDLE */
};
+/*
+ * Record entry into an extended quiescent state. This is only to be
+ * called when not already in an extended quiescent state.
+ */
+static void rcu_dynticks_eqs_enter(void)
+{
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+ int special;
+
+ /*
+ * CPUs seeing atomic_inc_return() must see prior RCU read-side
+ * critical sections, and we also must force ordering with the
+ * next idle sojourn.
+ */
+ special = atomic_inc_return(&rdtp->dynticks);
+ WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && special & 0x1);
+}
+
+/*
+ * Record exit from an extended quiescent state. This is only to be
+ * called from an extended quiescent state.
+ */
+static void rcu_dynticks_eqs_exit(void)
+{
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+ int special;
+
+ /*
+ * CPUs seeing atomic_inc_return() must see prior idle sojourns,
+ * and we also must force ordering with the next RCU read-side
+ * critical section.
+ */
+ special = atomic_inc_return(&rdtp->dynticks);
+ WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !(special & 0x1));
+}
+
+/*
+ * Reset the current CPU's ->dynticks counter to indicate that the
+ * newly onlined CPU is no longer in an extended quiescent state.
+ * This will either leave the counter unchanged, or increment it
+ * to the next non-quiescent value.
+ *
+ * The non-atomic test/increment sequence works because the upper bits
+ * of the ->dynticks counter are manipulated only by the corresponding CPU,
+ * or when the corresponding CPU is offline.
+ */
+static void rcu_dynticks_eqs_online(void)
+{
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+
+ if (atomic_read(&rdtp->dynticks) & 0x1)
+ return;
+ atomic_add(0x1, &rdtp->dynticks);
+}
+
+/*
+ * Is the current CPU in an extended quiescent state?
+ *
+ * No ordering, as we are sampling CPU-local information.
+ */
+bool rcu_dynticks_curr_cpu_in_eqs(void)
+{
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+
+ return !(atomic_read(&rdtp->dynticks) & 0x1);
+}
+
+/*
+ * Snapshot the ->dynticks counter with full ordering so as to allow
+ * stable comparison of this counter with past and future snapshots.
+ */
+int rcu_dynticks_snap(struct rcu_dynticks *rdtp)
+{
+ int snap = atomic_add_return(0, &rdtp->dynticks);
+
+ return snap;
+}
+
+/*
+ * Return true if the snapshot returned from rcu_dynticks_snap()
+ * indicates that RCU is in an extended quiescent state.
+ */
+static bool rcu_dynticks_in_eqs(int snap)
+{
+ return !(snap & 0x1);
+}
+
+/*
+ * Return true if the CPU corresponding to the specified rcu_dynticks
+ * structure has spent some time in an extended quiescent state since
+ * rcu_dynticks_snap() returned the specified snapshot.
+ */
+static bool rcu_dynticks_in_eqs_since(struct rcu_dynticks *rdtp, int snap)
+{
+ return snap != rcu_dynticks_snap(rdtp);
+}
+
+/*
+ * Do a double-increment of the ->dynticks counter to emulate a
+ * momentary idle-CPU quiescent state.
+ */
+static void rcu_dynticks_momentary_idle(void)
+{
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+ int special = atomic_add_return(2, &rdtp->dynticks);
+
+ /* It is illegal to call this from idle state. */
+ WARN_ON_ONCE(!(special & 0x1));
+}
+
DEFINE_PER_CPU_SHARED_ALIGNED(unsigned long, rcu_qs_ctr);
EXPORT_PER_CPU_SYMBOL_GPL(rcu_qs_ctr);
@@ -300,7 +410,6 @@ EXPORT_PER_CPU_SYMBOL_GPL(rcu_qs_ctr);
static void rcu_momentary_dyntick_idle(void)
{
struct rcu_data *rdp;
- struct rcu_dynticks *rdtp;
int resched_mask;
struct rcu_state *rsp;
@@ -327,10 +436,7 @@ static void rcu_momentary_dyntick_idle(void)
* quiescent state, with no need for this CPU to do anything
* further.
*/
- rdtp = this_cpu_ptr(&rcu_dynticks);
- smp_mb__before_atomic(); /* Earlier stuff before QS. */
- atomic_add(2, &rdtp->dynticks); /* QS. */
- smp_mb__after_atomic(); /* Later stuff after QS. */
+ rcu_dynticks_momentary_idle();
break;
}
}
@@ -611,7 +717,7 @@ static int
cpu_has_callbacks_ready_to_invoke(struct rcu_data *rdp)
{
return &rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL] &&
- rdp->nxttail[RCU_DONE_TAIL] != NULL;
+ rdp->nxttail[RCU_NEXT_TAIL] != NULL;
}
/*
@@ -673,7 +779,7 @@ static void rcu_eqs_enter_common(long long oldval, bool user)
{
struct rcu_state *rsp;
struct rcu_data *rdp;
- struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+ RCU_TRACE(struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);)
trace_rcu_dyntick(TPS("Start"), oldval, rdtp->dynticks_nesting);
if (IS_ENABLED(CONFIG_RCU_EQS_DEBUG) &&
@@ -692,12 +798,7 @@ static void rcu_eqs_enter_common(long long oldval, bool user)
do_nocb_deferred_wakeup(rdp);
}
rcu_prepare_for_idle();
- /* CPUs seeing atomic_inc() must see prior RCU read-side crit sects */
- smp_mb__before_atomic(); /* See above. */
- atomic_inc(&rdtp->dynticks);
- smp_mb__after_atomic(); /* Force ordering with next sojourn. */
- WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) &&
- atomic_read(&rdtp->dynticks) & 0x1);
+ rcu_dynticks_eqs_enter();
rcu_dynticks_task_enter();
/*
@@ -826,15 +927,10 @@ void rcu_irq_exit_irqson(void)
*/
static void rcu_eqs_exit_common(long long oldval, int user)
{
- struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
+ RCU_TRACE(struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);)
rcu_dynticks_task_exit();
- smp_mb__before_atomic(); /* Force ordering w/previous sojourn. */
- atomic_inc(&rdtp->dynticks);
- /* CPUs seeing atomic_inc() must see later RCU read-side crit sects */
- smp_mb__after_atomic(); /* See above. */
- WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) &&
- !(atomic_read(&rdtp->dynticks) & 0x1));
+ rcu_dynticks_eqs_exit();
rcu_cleanup_after_idle();
trace_rcu_dyntick(TPS("End"), oldval, rdtp->dynticks_nesting);
if (IS_ENABLED(CONFIG_RCU_EQS_DEBUG) &&
@@ -980,12 +1076,8 @@ void rcu_nmi_enter(void)
* to be in the outermost NMI handler that interrupted an RCU-idle
* period (observation due to Andy Lutomirski).
*/
- if (!(atomic_read(&rdtp->dynticks) & 0x1)) {
- smp_mb__before_atomic(); /* Force delay from prior write. */
- atomic_inc(&rdtp->dynticks);
- /* atomic_inc() before later RCU read-side crit sects */
- smp_mb__after_atomic(); /* See above. */
- WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1));
+ if (rcu_dynticks_curr_cpu_in_eqs()) {
+ rcu_dynticks_eqs_exit();
incby = 1;
}
rdtp->dynticks_nmi_nesting += incby;
@@ -1010,7 +1102,7 @@ void rcu_nmi_exit(void)
* to us!)
*/
WARN_ON_ONCE(rdtp->dynticks_nmi_nesting <= 0);
- WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1));
+ WARN_ON_ONCE(rcu_dynticks_curr_cpu_in_eqs());
/*
* If the nesting level is not 1, the CPU wasn't RCU-idle, so
@@ -1023,11 +1115,7 @@ void rcu_nmi_exit(void)
/* This NMI interrupted an RCU-idle CPU, restore RCU-idleness. */
rdtp->dynticks_nmi_nesting = 0;
- /* CPUs seeing atomic_inc() must see prior RCU read-side crit sects */
- smp_mb__before_atomic(); /* See above. */
- atomic_inc(&rdtp->dynticks);
- smp_mb__after_atomic(); /* Force delay to next write. */
- WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1);
+ rcu_dynticks_eqs_enter();
}
/**
@@ -1040,7 +1128,7 @@ void rcu_nmi_exit(void)
*/
bool notrace __rcu_is_watching(void)
{
- return atomic_read(this_cpu_ptr(&rcu_dynticks.dynticks)) & 0x1;
+ return !rcu_dynticks_curr_cpu_in_eqs();
}
/**
@@ -1123,9 +1211,9 @@ static int rcu_is_cpu_rrupt_from_idle(void)
static int dyntick_save_progress_counter(struct rcu_data *rdp,
bool *isidle, unsigned long *maxj)
{
- rdp->dynticks_snap = atomic_add_return(0, &rdp->dynticks->dynticks);
+ rdp->dynticks_snap = rcu_dynticks_snap(rdp->dynticks);
rcu_sysidle_check_cpu(rdp, isidle, maxj);
- if ((rdp->dynticks_snap & 0x1) == 0) {
+ if (rcu_dynticks_in_eqs(rdp->dynticks_snap)) {
trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("dti"));
if (ULONG_CMP_LT(READ_ONCE(rdp->gpnum) + ULONG_MAX / 4,
rdp->mynode->gpnum))
@@ -1144,12 +1232,10 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp,
static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
bool *isidle, unsigned long *maxj)
{
- unsigned int curr;
+ unsigned long jtsq;
int *rcrmp;
- unsigned int snap;
-
- curr = (unsigned int)atomic_add_return(0, &rdp->dynticks->dynticks);
- snap = (unsigned int)rdp->dynticks_snap;
+ unsigned long rjtsc;
+ struct rcu_node *rnp;
/*
* If the CPU passed through or entered a dynticks idle phase with
@@ -1159,27 +1245,39 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
* read-side critical section that started before the beginning
* of the current RCU grace period.
*/
- if ((curr & 0x1) == 0 || UINT_CMP_GE(curr, snap + 2)) {
+ if (rcu_dynticks_in_eqs_since(rdp->dynticks, rdp->dynticks_snap)) {
trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("dti"));
rdp->dynticks_fqs++;
return 1;
}
+ /* Compute and saturate jiffies_till_sched_qs. */
+ jtsq = jiffies_till_sched_qs;
+ rjtsc = rcu_jiffies_till_stall_check();
+ if (jtsq > rjtsc / 2) {
+ WRITE_ONCE(jiffies_till_sched_qs, rjtsc);
+ jtsq = rjtsc / 2;
+ } else if (jtsq < 1) {
+ WRITE_ONCE(jiffies_till_sched_qs, 1);
+ jtsq = 1;
+ }
+
/*
- * Check for the CPU being offline, but only if the grace period
- * is old enough. We don't need to worry about the CPU changing
- * state: If we see it offline even once, it has been through a
- * quiescent state.
- *
- * The reason for insisting that the grace period be at least
- * one jiffy old is that CPUs that are not quite online and that
- * have just gone offline can still execute RCU read-side critical
- * sections.
+ * Has this CPU encountered a cond_resched_rcu_qs() since the
+ * beginning of the grace period? For this to be the case,
+ * the CPU has to have noticed the current grace period. This
+ * might not be the case for nohz_full CPUs looping in the kernel.
*/
- if (ULONG_CMP_GE(rdp->rsp->gp_start + 2, jiffies))
- return 0; /* Grace period is not old enough. */
- barrier();
- if (cpu_is_offline(rdp->cpu)) {
+ rnp = rdp->mynode;
+ if (time_after(jiffies, rdp->rsp->gp_start + jtsq) &&
+ READ_ONCE(rdp->rcu_qs_ctr_snap) != per_cpu(rcu_qs_ctr, rdp->cpu) &&
+ READ_ONCE(rdp->gpnum) == rnp->gpnum && !rdp->gpwrap) {
+ trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("rqc"));
+ return 1;
+ }
+
+ /* Check for the CPU being offline. */
+ if (!(rdp->grpmask & rcu_rnp_online_cpus(rnp))) {
trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("ofl"));
rdp->offline_fqs++;
return 1;
@@ -1207,9 +1305,8 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
* warning delay.
*/
rcrmp = &per_cpu(rcu_sched_qs_mask, rdp->cpu);
- if (ULONG_CMP_GE(jiffies,
- rdp->rsp->gp_start + jiffies_till_sched_qs) ||
- ULONG_CMP_GE(jiffies, rdp->rsp->jiffies_resched)) {
+ if (time_after(jiffies, rdp->rsp->gp_start + jtsq) ||
+ time_after(jiffies, rdp->rsp->jiffies_resched)) {
if (!(READ_ONCE(*rcrmp) & rdp->rsp->flavor_mask)) {
WRITE_ONCE(rdp->cond_resched_completed,
READ_ONCE(rdp->mynode->completed));
@@ -1220,11 +1317,12 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
rdp->rsp->jiffies_resched += 5; /* Re-enable beating. */
}
- /* And if it has been a really long time, kick the CPU as well. */
- if (ULONG_CMP_GE(jiffies,
- rdp->rsp->gp_start + 2 * jiffies_till_sched_qs) ||
- ULONG_CMP_GE(jiffies, rdp->rsp->gp_start + jiffies_till_sched_qs))
- resched_cpu(rdp->cpu); /* Force CPU into scheduler. */
+ /*
+ * If more than halfway to RCU CPU stall-warning time, do
+ * a resched_cpu() to try to loosen things up a bit.
+ */
+ if (jiffies - rdp->rsp->gp_start > rcu_jiffies_till_stall_check() / 2)
+ resched_cpu(rdp->cpu);
return 0;
}
@@ -1277,7 +1375,10 @@ static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp)
}
/*
- * Dump stacks of all tasks running on stalled CPUs.
+ * Dump stacks of all tasks running on stalled CPUs. First try using
+ * NMIs, but fall back to manual remote stack tracing on architectures
+ * that don't support NMI-based stack dumps. The NMI-triggered stack
+ * traces are more accurate because they are printed by the target CPU.
*/
static void rcu_dump_cpu_stacks(struct rcu_state *rsp)
{
@@ -1287,11 +1388,10 @@ static void rcu_dump_cpu_stacks(struct rcu_state *rsp)
rcu_for_each_leaf_node(rsp, rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
- if (rnp->qsmask != 0) {
- for_each_leaf_node_possible_cpu(rnp, cpu)
- if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu))
+ for_each_leaf_node_possible_cpu(rnp, cpu)
+ if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu))
+ if (!trigger_single_cpu_backtrace(cpu))
dump_cpu_task(cpu);
- }
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
}
@@ -1379,6 +1479,9 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum)
(long)rsp->gpnum, (long)rsp->completed, totqlen);
if (ndetected) {
rcu_dump_cpu_stacks(rsp);
+
+ /* Complain about tasks blocking the grace period. */
+ rcu_print_detail_task_stall(rsp);
} else {
if (READ_ONCE(rsp->gpnum) != gpnum ||
READ_ONCE(rsp->completed) == gpnum) {
@@ -1395,9 +1498,6 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum)
}
}
- /* Complain about tasks blocking the grace period. */
- rcu_print_detail_task_stall(rsp);
-
rcu_check_gp_kthread_starvation(rsp);
panic_on_rcu_stall();
@@ -2467,10 +2567,8 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
rnp = rdp->mynode;
raw_spin_lock_irqsave_rcu_node(rnp, flags);
- if ((rdp->cpu_no_qs.b.norm &&
- rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) ||
- rdp->gpnum != rnp->gpnum || rnp->completed == rnp->gpnum ||
- rdp->gpwrap) {
+ if (rdp->cpu_no_qs.b.norm || rdp->gpnum != rnp->gpnum ||
+ rnp->completed == rnp->gpnum || rdp->gpwrap) {
/*
* The grace period in which this quiescent state was
@@ -2525,8 +2623,7 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp)
* Was there a quiescent state since the beginning of the grace
* period? If no, then exit and wait for the next call.
*/
- if (rdp->cpu_no_qs.b.norm &&
- rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr))
+ if (rdp->cpu_no_qs.b.norm)
return;
/*
@@ -3480,9 +3577,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
rdp->core_needs_qs && rdp->cpu_no_qs.b.norm &&
rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) {
rdp->n_rp_core_needs_qs++;
- } else if (rdp->core_needs_qs &&
- (!rdp->cpu_no_qs.b.norm ||
- rdp->rcu_qs_ctr_snap != __this_cpu_read(rcu_qs_ctr))) {
+ } else if (rdp->core_needs_qs && !rdp->cpu_no_qs.b.norm) {
rdp->n_rp_report_qs++;
return 1;
}
@@ -3748,7 +3843,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
rdp->grpmask = leaf_node_cpu_bit(rdp->mynode, cpu);
rdp->dynticks = &per_cpu(rcu_dynticks, cpu);
WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != DYNTICK_TASK_EXIT_IDLE);
- WARN_ON_ONCE(atomic_read(&rdp->dynticks->dynticks) != 1);
+ WARN_ON_ONCE(rcu_dynticks_in_eqs(rcu_dynticks_snap(rdp->dynticks)));
rdp->cpu = cpu;
rdp->rsp = rsp;
rcu_boot_init_nocb_percpu_data(rdp);
@@ -3765,7 +3860,6 @@ static void
rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
{
unsigned long flags;
- unsigned long mask;
struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
struct rcu_node *rnp = rcu_get_root(rsp);
@@ -3778,8 +3872,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
init_callback_list(rdp); /* Re-enable callbacks on this CPU. */
rdp->dynticks->dynticks_nesting = DYNTICK_TASK_EXIT_IDLE;
rcu_sysidle_init_percpu_data(rdp->dynticks);
- atomic_set(&rdp->dynticks->dynticks,
- (atomic_read(&rdp->dynticks->dynticks) & ~0x1) + 1);
+ rcu_dynticks_eqs_online();
raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */
/*
@@ -3788,7 +3881,6 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
* of the next grace period.
*/
rnp = rdp->mynode;
- mask = rdp->grpmask;
raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
if (!rdp->beenonline)
WRITE_ONCE(rsp->ncpus, READ_ONCE(rsp->ncpus) + 1);
@@ -3872,7 +3964,7 @@ void rcu_cpu_starting(unsigned int cpu)
struct rcu_state *rsp;
for_each_rcu_flavor(rsp) {
- rdp = this_cpu_ptr(rsp->rda);
+ rdp = per_cpu_ptr(rsp->rda, cpu);
rnp = rdp->mynode;
mask = rdp->grpmask;
raw_spin_lock_irqsave_rcu_node(rnp, flags);
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index fe98dd24adf8..b60f2b6caa14 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -521,7 +521,6 @@ struct rcu_state {
struct mutex exp_mutex; /* Serialize expedited GP. */
struct mutex exp_wake_mutex; /* Serialize wakeup. */
unsigned long expedited_sequence; /* Take a ticket. */
- atomic_long_t expedited_normal; /* # fallbacks to normal. */
atomic_t expedited_need_qs; /* # CPUs left to check in. */
struct swait_queue_head expedited_wq; /* Wait for check-ins. */
int ncpus_snap; /* # CPUs seen last time. */
@@ -595,6 +594,8 @@ extern struct rcu_state rcu_bh_state;
extern struct rcu_state rcu_preempt_state;
#endif /* #ifdef CONFIG_PREEMPT_RCU */
+int rcu_dynticks_snap(struct rcu_dynticks *rdtp);
+
#ifdef CONFIG_RCU_BOOST
DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu);
@@ -688,18 +689,6 @@ static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll)
#endif /* #ifdef CONFIG_RCU_TRACE */
/*
- * Place this after a lock-acquisition primitive to guarantee that
- * an UNLOCK+LOCK pair act as a full barrier. This guarantee applies
- * if the UNLOCK and LOCK are executed by the same CPU or if the
- * UNLOCK and LOCK operate on the same lock variable.
- */
-#ifdef CONFIG_PPC
-#define smp_mb__after_unlock_lock() smp_mb() /* Full ordering for lock. */
-#else /* #ifdef CONFIG_PPC */
-#define smp_mb__after_unlock_lock() do { } while (0)
-#endif /* #else #ifdef CONFIG_PPC */
-
-/*
* Wrappers for the rcu_node::lock acquire and release.
*
* Because the rcu_nodes form a tree, the tree traversal locking will observe
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index e59e1849b89a..a7b639ccd46e 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -20,16 +20,26 @@
* Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
*/
-/* Wrapper functions for expedited grace periods. */
+/*
+ * Record the start of an expedited grace period.
+ */
static void rcu_exp_gp_seq_start(struct rcu_state *rsp)
{
rcu_seq_start(&rsp->expedited_sequence);
}
+
+/*
+ * Record the end of an expedited grace period.
+ */
static void rcu_exp_gp_seq_end(struct rcu_state *rsp)
{
rcu_seq_end(&rsp->expedited_sequence);
smp_mb(); /* Ensure that consecutive grace periods serialize. */
}
+
+/*
+ * Take a snapshot of the expedited-grace-period counter.
+ */
static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)
{
unsigned long s;
@@ -39,6 +49,12 @@ static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)
trace_rcu_exp_grace_period(rsp->name, s, TPS("snap"));
return s;
}
+
+/*
+ * Given a counter snapshot from rcu_exp_gp_seq_snap(), return true
+ * if a full expedited grace period has elapsed since that snapshot
+ * was taken.
+ */
static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s)
{
return rcu_seq_done(&rsp->expedited_sequence, s);
@@ -356,12 +372,11 @@ static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
mask_ofl_test = 0;
for_each_leaf_node_possible_cpu(rnp, cpu) {
struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
- struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
rdp->exp_dynticks_snap =
- atomic_add_return(0, &rdtp->dynticks);
+ rcu_dynticks_snap(rdp->dynticks);
if (raw_smp_processor_id() == cpu ||
- !(rdp->exp_dynticks_snap & 0x1) ||
+ rcu_dynticks_in_eqs(rdp->exp_dynticks_snap) ||
!(rnp->qsmaskinitnext & rdp->grpmask))
mask_ofl_test |= rdp->grpmask;
}
@@ -380,13 +395,12 @@ static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
for_each_leaf_node_possible_cpu(rnp, cpu) {
unsigned long mask = leaf_node_cpu_bit(rnp, cpu);
struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
- struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
if (!(mask_ofl_ipi & mask))
continue;
retry_ipi:
- if (atomic_add_return(0, &rdtp->dynticks) !=
- rdp->exp_dynticks_snap) {
+ if (rcu_dynticks_in_eqs_since(rdp->dynticks,
+ rdp->exp_dynticks_snap)) {
mask_ofl_test |= mask;
continue;
}
@@ -623,6 +637,11 @@ void synchronize_sched_expedited(void)
{
struct rcu_state *rsp = &rcu_sched_state;
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+ lock_is_held(&rcu_lock_map) ||
+ lock_is_held(&rcu_sched_lock_map),
+ "Illegal synchronize_sched_expedited() in RCU read-side critical section");
+
/* If only one CPU, this is automatically a grace period. */
if (rcu_blocking_is_gp())
return;
@@ -692,6 +711,11 @@ void synchronize_rcu_expedited(void)
{
struct rcu_state *rsp = rcu_state_p;
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+ lock_is_held(&rcu_lock_map) ||
+ lock_is_held(&rcu_sched_lock_map),
+ "Illegal synchronize_rcu_expedited() in RCU read-side critical section");
+
if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
return;
_synchronize_rcu_expedited(rsp, sync_rcu_exp_handler);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 56583e764ebf..a240f3308be6 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1643,7 +1643,7 @@ static void print_cpu_stall_info(struct rcu_state *rsp, int cpu)
"o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)],
"N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)],
ticks_value, ticks_title,
- atomic_read(&rdtp->dynticks) & 0xfff,
+ rcu_dynticks_snap(rdtp) & 0xfff,
rdtp->dynticks_nesting, rdtp->dynticks_nmi_nesting,
rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu),
READ_ONCE(rsp->n_force_qs) - rsp->n_force_qs_gpstart,
@@ -2366,8 +2366,9 @@ static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp)
}
/*
- * Each pass through this loop sets up one rcu_data structure and
- * spawns one rcu_nocb_kthread().
+ * Each pass through this loop sets up one rcu_data structure.
+ * Should the corresponding CPU come online in the future, then
+ * we will spawn the needed set of rcu_nocb_kthread() kthreads.
*/
for_each_cpu(cpu, rcu_nocb_mask) {
rdp = per_cpu_ptr(rsp->rda, cpu);
diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c
index b1f28972872c..8751a748499a 100644
--- a/kernel/rcu/tree_trace.c
+++ b/kernel/rcu/tree_trace.c
@@ -124,7 +124,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
rdp->rcu_qs_ctr_snap == per_cpu(rcu_qs_ctr, rdp->cpu),
rdp->core_needs_qs);
seq_printf(m, " dt=%d/%llx/%d df=%lu",
- atomic_read(&rdp->dynticks->dynticks),
+ rcu_dynticks_snap(rdp->dynticks),
rdp->dynticks->dynticks_nesting,
rdp->dynticks->dynticks_nmi_nesting,
rdp->dynticks_fqs);
@@ -194,9 +194,8 @@ static int show_rcuexp(struct seq_file *m, void *v)
s2 += atomic_long_read(&rdp->exp_workdone2);
s3 += atomic_long_read(&rdp->exp_workdone3);
}
- seq_printf(m, "s=%lu wd0=%lu wd1=%lu wd2=%lu wd3=%lu n=%lu enq=%d sc=%lu\n",
+ seq_printf(m, "s=%lu wd0=%lu wd1=%lu wd2=%lu wd3=%lu enq=%d sc=%lu\n",
rsp->expedited_sequence, s0, s1, s2, s3,
- atomic_long_read(&rsp->expedited_normal),
atomic_read(&rsp->expedited_need_qs),
rsp->expedited_sequence / 2);
return 0;
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 4f6db7e6a117..9e03db9ea9c0 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -132,8 +132,7 @@ bool rcu_gp_is_normal(void)
}
EXPORT_SYMBOL_GPL(rcu_gp_is_normal);
-static atomic_t rcu_expedited_nesting =
- ATOMIC_INIT(IS_ENABLED(CONFIG_RCU_EXPEDITE_BOOT) ? 1 : 0);
+static atomic_t rcu_expedited_nesting = ATOMIC_INIT(1);
/*
* Should normal grace-period primitives be expedited? Intended for
@@ -182,8 +181,7 @@ EXPORT_SYMBOL_GPL(rcu_unexpedite_gp);
*/
void rcu_end_inkernel_boot(void)
{
- if (IS_ENABLED(CONFIG_RCU_EXPEDITE_BOOT))
- rcu_unexpedite_gp();
+ rcu_unexpedite_gp();
if (rcu_normal_after_boot)
WRITE_ONCE(rcu_normal, 1);
}
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index b06848a104e6..5655bd95919a 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1450,6 +1450,7 @@ config RCU_CPU_STALL_TIMEOUT
config RCU_TRACE
bool "Enable tracing for RCU"
depends on DEBUG_KERNEL
+ default y if TREE_RCU
select TRACE_CLOCK
help
This option provides tracing in RCU which presents stats
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/CFcommon b/tools/testing/selftests/rcutorture/configs/rcu/CFcommon
index f824b4c9d9d9..d2d2a86139db 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/CFcommon
+++ b/tools/testing/selftests/rcutorture/configs/rcu/CFcommon
@@ -1,5 +1,2 @@
CONFIG_RCU_TORTURE_TEST=y
CONFIG_PRINTK_TIME=y
-CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
-CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
-CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TINY01 b/tools/testing/selftests/rcutorture/configs/rcu/TINY01
index 0a63e073a00c..6db705e55487 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TINY01
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TINY01
@@ -7,6 +7,7 @@ CONFIG_HZ_PERIODIC=n
CONFIG_NO_HZ_IDLE=y
CONFIG_NO_HZ_FULL=n
CONFIG_RCU_TRACE=n
+#CHECK#CONFIG_RCU_STALL_COMMON=n
CONFIG_DEBUG_LOCK_ALLOC=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_PREEMPT_COUNT=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TINY02 b/tools/testing/selftests/rcutorture/configs/rcu/TINY02
index f1892e0371c9..a59f7686e219 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TINY02
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TINY02
@@ -8,7 +8,8 @@ CONFIG_NO_HZ_IDLE=n
CONFIG_NO_HZ_FULL=n
CONFIG_RCU_TRACE=y
CONFIG_PROVE_LOCKING=y
+CONFIG_PROVE_RCU_REPEATEDLY=y
#CHECK#CONFIG_PROVE_RCU=y
CONFIG_DEBUG_LOCK_ALLOC=y
-CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
CONFIG_PREEMPT_COUNT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE01 b/tools/testing/selftests/rcutorture/configs/rcu/TREE01
index f572b873c620..359cb258f639 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE01
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE01
@@ -16,3 +16,6 @@ CONFIG_DEBUG_LOCK_ALLOC=n
CONFIG_RCU_BOOST=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
+CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE02 b/tools/testing/selftests/rcutorture/configs/rcu/TREE02
index ef6a22c44dea..c1ab5926568b 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE02
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE02
@@ -20,3 +20,7 @@ CONFIG_PROVE_LOCKING=n
CONFIG_RCU_BOOST=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
+CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE03 b/tools/testing/selftests/rcutorture/configs/rcu/TREE03
index 7a17c503b382..3b93ee544e70 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE03
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE03
@@ -17,3 +17,6 @@ CONFIG_RCU_BOOST=y
CONFIG_RCU_KTHREAD_PRIO=2
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
+CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE04 b/tools/testing/selftests/rcutorture/configs/rcu/TREE04
index 17cbe098b115..5af758e783c7 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE04
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE04
@@ -19,3 +19,7 @@ CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
+CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y
+CONFIG_RCU_EQS_DEBUG=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE05 b/tools/testing/selftests/rcutorture/configs/rcu/TREE05
index 1257d3227b1e..d4cdc0d74e16 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE05
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE05
@@ -19,3 +19,6 @@ CONFIG_PROVE_LOCKING=y
#CHECK#CONFIG_PROVE_RCU=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
+CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE06 b/tools/testing/selftests/rcutorture/configs/rcu/TREE06
index d3e456b74cbe..4cb02bd28f08 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE06
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE06
@@ -20,3 +20,6 @@ CONFIG_PROVE_LOCKING=y
#CHECK#CONFIG_PROVE_RCU=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
CONFIG_RCU_EXPERT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
+CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE07 b/tools/testing/selftests/rcutorture/configs/rcu/TREE07
index 3956b4131f72..b12a3ea1867e 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE07
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE07
@@ -19,3 +19,6 @@ CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP=y
+CONFIG_RCU_TORTURE_TEST_SLOW_INIT=y
+CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE08 b/tools/testing/selftests/rcutorture/configs/rcu/TREE08
index bb9b0c1a23c2..099cc63c6a3b 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE08
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE08
@@ -17,8 +17,8 @@ CONFIG_RCU_FANOUT_LEAF=2
CONFIG_RCU_NOCB_CPU=y
CONFIG_RCU_NOCB_CPU_ALL=y
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_PROVE_LOCKING=y
-#CHECK#CONFIG_PROVE_RCU=y
+CONFIG_PROVE_LOCKING=n
CONFIG_RCU_BOOST=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
+CONFIG_RCU_EQS_DEBUG=y
diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
index 4e2b1893d40d..364801b1a230 100644
--- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
+++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
@@ -14,6 +14,7 @@ CONFIG_NO_HZ_FULL_SYSIDLE -- Do one.
CONFIG_PREEMPT -- Do half. (First three and #8.)
CONFIG_PROVE_LOCKING -- Do several, covering CONFIG_DEBUG_LOCK_ALLOC=y and not.
CONFIG_PROVE_RCU -- Hardwired to CONFIG_PROVE_LOCKING.
+CONFIG_PROVE_RCU_REPEATEDLY -- Do one.
CONFIG_RCU_BOOST -- one of PREEMPT_RCU.
CONFIG_RCU_KTHREAD_PRIO -- set to 2 for _BOOST testing.
CONFIG_RCU_FANOUT -- Cover hierarchy, but overlap with others.
@@ -25,7 +26,12 @@ CONFIG_RCU_NOCB_CPU_NONE -- Do one.
CONFIG_RCU_NOCB_CPU_ZERO -- Do one.
CONFIG_RCU_TRACE -- Do half.
CONFIG_SMP -- Need one !SMP for PREEMPT_RCU.
-!RCU_EXPERT -- Do a few, but these have to be vanilla configurations.
+CONFIG_RCU_EXPERT=n -- Do a few, but these have to be vanilla configurations.
+CONFIG_RCU_EQS_DEBUG -- Do at least one for CONFIG_NO_HZ_FULL and not.
+CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP -- Do for all but a couple TREE scenarios.
+CONFIG_RCU_TORTURE_TEST_SLOW_INIT -- Do for all but a couple TREE scenarios.
+CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT -- Do for all but a couple TREE scenarios.
+
RCU-bh: Do one with PREEMPT and one with !PREEMPT.
RCU-sched: Do one with PREEMPT but not BOOST.
@@ -72,7 +78,30 @@ CONFIG_RCU_TORTURE_TEST_RUNNABLE
Always used in KVM testing.
+CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT_DELAY
+CONFIG_RCU_TORTURE_TEST_SLOW_INIT_DELAY
+CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY
+
+ Inspection suffices, ignore.
+
CONFIG_PREEMPT_RCU
CONFIG_TREE_RCU
+CONFIG_TINY_RCU
+
+ These are controlled by CONFIG_PREEMPT and/or CONFIG_SMP.
+
+CONFIG_SPARSE_RCU_POINTER
+
+ Makes sense only for sparse runs, not for kernel builds.
+
+CONFIG_SRCU
+CONFIG_TASKS_RCU
+
+ Selected by CONFIG_RCU_TORTURE_TEST, so cannot disable.
+
+CONFIG_RCU_TRACE
+
+ Implied by CONFIG_RCU_TRACE for Tree RCU.
+
- These are controlled by CONFIG_PREEMPT.
+boot parameters ignored: TBD
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/.gitignore b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/.gitignore
new file mode 100644
index 000000000000..712a3d41a325
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/.gitignore
@@ -0,0 +1 @@
+srcu.c
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/Makefile b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/Makefile
new file mode 100644
index 000000000000..16b01559fa55
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/Makefile
@@ -0,0 +1,16 @@
+all: srcu.c store_buffering
+
+LINUX_SOURCE = ../../../../../..
+
+modified_srcu_input = $(LINUX_SOURCE)/include/linux/srcu.h \
+ $(LINUX_SOURCE)/kernel/rcu/srcu.c
+
+modified_srcu_output = include/linux/srcu.h srcu.c
+
+include/linux/srcu.h: srcu.c
+
+srcu.c: modify_srcu.awk Makefile $(modified_srcu_input)
+ awk -f modify_srcu.awk $(modified_srcu_input) $(modified_srcu_output)
+
+store_buffering:
+ @cd tests/store_buffering; make
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/delay.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/delay.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/delay.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/export.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/export.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/export.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/mutex.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/mutex.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/mutex.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/percpu.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/percpu.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/percpu.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/preempt.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/preempt.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/preempt.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/rcupdate.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/rcupdate.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/rcupdate.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/sched.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/sched.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/sched.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/smp.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/smp.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/smp.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/workqueue.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/workqueue.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/linux/workqueue.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/uapi/linux/types.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/uapi/linux/types.h
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/empty_includes/uapi/linux/types.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/.gitignore b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/.gitignore
new file mode 100644
index 000000000000..1d016e66980a
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/.gitignore
@@ -0,0 +1 @@
+srcu.h
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/kconfig.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/kconfig.h
new file mode 100644
index 000000000000..f2860dd1b407
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/kconfig.h
@@ -0,0 +1 @@
+#include <LINUX_SOURCE/linux/kconfig.h>
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/types.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/types.h
new file mode 100644
index 000000000000..4a3d538fef12
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/include/linux/types.h
@@ -0,0 +1,155 @@
+/*
+ * This header has been modifies to remove definitions of types that
+ * are defined in standard userspace headers or are problematic for some
+ * other reason.
+ */
+
+#ifndef _LINUX_TYPES_H
+#define _LINUX_TYPES_H
+
+#define __EXPORTED_HEADERS__
+#include <uapi/linux/types.h>
+
+#ifndef __ASSEMBLY__
+
+#define DECLARE_BITMAP(name, bits) \
+ unsigned long name[BITS_TO_LONGS(bits)]
+
+typedef __u32 __kernel_dev_t;
+
+/* bsd */
+typedef unsigned char u_char;
+typedef unsigned short u_short;
+typedef unsigned int u_int;
+typedef unsigned long u_long;
+
+/* sysv */
+typedef unsigned char unchar;
+typedef unsigned short ushort;
+typedef unsigned int uint;
+typedef unsigned long ulong;
+
+#ifndef __BIT_TYPES_DEFINED__
+#define __BIT_TYPES_DEFINED__
+
+typedef __u8 u_int8_t;
+typedef __s8 int8_t;
+typedef __u16 u_int16_t;
+typedef __s16 int16_t;
+typedef __u32 u_int32_t;
+typedef __s32 int32_t;
+
+#endif /* !(__BIT_TYPES_DEFINED__) */
+
+typedef __u8 uint8_t;
+typedef __u16 uint16_t;
+typedef __u32 uint32_t;
+
+/* this is a special 64bit data type that is 8-byte aligned */
+#define aligned_u64 __u64 __attribute__((aligned(8)))
+#define aligned_be64 __be64 __attribute__((aligned(8)))
+#define aligned_le64 __le64 __attribute__((aligned(8)))
+
+/**
+ * The type used for indexing onto a disc or disc partition.
+ *
+ * Linux always considers sectors to be 512 bytes long independently
+ * of the devices real block size.
+ *
+ * blkcnt_t is the type of the inode's block count.
+ */
+#ifdef CONFIG_LBDAF
+typedef u64 sector_t;
+#else
+typedef unsigned long sector_t;
+#endif
+
+/*
+ * The type of an index into the pagecache.
+ */
+#define pgoff_t unsigned long
+
+/*
+ * A dma_addr_t can hold any valid DMA address, i.e., any address returned
+ * by the DMA API.
+ *
+ * If the DMA API only uses 32-bit addresses, dma_addr_t need only be 32
+ * bits wide. Bus addresses, e.g., PCI BARs, may be wider than 32 bits,
+ * but drivers do memory-mapped I/O to ioremapped kernel virtual addresses,
+ * so they don't care about the size of the actual bus addresses.
+ */
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+typedef u64 dma_addr_t;
+#else
+typedef u32 dma_addr_t;
+#endif
+
+#ifdef CONFIG_PHYS_ADDR_T_64BIT
+typedef u64 phys_addr_t;
+#else
+typedef u32 phys_addr_t;
+#endif
+
+typedef phys_addr_t resource_size_t;
+
+/*
+ * This type is the placeholder for a hardware interrupt number. It has to be
+ * big enough to enclose whatever representation is used by a given platform.
+ */
+typedef unsigned long irq_hw_number_t;
+
+typedef struct {
+ int counter;
+} atomic_t;
+
+#ifdef CONFIG_64BIT
+typedef struct {
+ long counter;
+} atomic64_t;
+#endif
+
+struct list_head {
+ struct list_head *next, *prev;
+};
+
+struct hlist_head {
+ struct hlist_node *first;
+};
+
+struct hlist_node {
+ struct hlist_node *next, **pprev;
+};
+
+/**
+ * struct callback_head - callback structure for use with RCU and task_work
+ * @next: next update requests in a list
+ * @func: actual update function to call after the grace period.
+ *
+ * The struct is aligned to size of pointer. On most architectures it happens
+ * naturally due ABI requirements, but some architectures (like CRIS) have
+ * weird ABI and we need to ask it explicitly.
+ *
+ * The alignment is required to guarantee that bits 0 and 1 of @next will be
+ * clear under normal conditions -- as long as we use call_rcu(),
+ * call_rcu_bh(), call_rcu_sched(), or call_srcu() to queue callback.
+ *
+ * This guarantee is important for few reasons:
+ * - future call_rcu_lazy() will make use of lower bits in the pointer;
+ * - the structure shares storage spacer in struct page with @compound_head,
+ * which encode PageTail() in bit 0. The guarantee is needed to avoid
+ * false-positive PageTail().
+ */
+struct callback_head {
+ struct callback_head *next;
+ void (*func)(struct callback_head *head);
+} __attribute__((aligned(sizeof(void *))));
+#define rcu_head callback_head
+
+typedef void (*rcu_callback_t)(struct rcu_head *head);
+typedef void (*call_rcu_func_t)(struct rcu_head *head, rcu_callback_t func);
+
+/* clocksource cycle base type */
+typedef u64 cycle_t;
+
+#endif /* __ASSEMBLY__ */
+#endif /* _LINUX_TYPES_H */
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/modify_srcu.awk b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/modify_srcu.awk
new file mode 100755
index 000000000000..8ff89043d0a9
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/modify_srcu.awk
@@ -0,0 +1,375 @@
+#!/bin/awk -f
+
+# Modify SRCU for formal verification. The first argument should be srcu.h and
+# the second should be srcu.c. Outputs modified srcu.h and srcu.c into the
+# current directory.
+
+BEGIN {
+ if (ARGC != 5) {
+ print "Usange: input.h input.c output.h output.c" > "/dev/stderr";
+ exit 1;
+ }
+ h_output = ARGV[3];
+ c_output = ARGV[4];
+ ARGC = 3;
+
+ # Tokenize using FS and not RS as FS supports regular expressions. Each
+ # record is one line of source, except that backslashed lines are
+ # combined. Comments are treated as field separators, as are quotes.
+ quote_regexp="\"([^\\\\\"]|\\\\.)*\"";
+ comment_regexp="\\/\\*([^*]|\\*+[^*/])*\\*\\/|\\/\\/.*(\n|$)";
+ FS="([ \\\\\t\n\v\f;,.=(){}+*/<>&|^-]|\\[|\\]|" comment_regexp "|" quote_regexp ")+";
+
+ inside_srcu_struct = 0;
+ inside_srcu_init_def = 0;
+ srcu_init_param_name = "";
+ in_macro = 0;
+ brace_nesting = 0;
+ paren_nesting = 0;
+
+ # Allow the manipulation of the last field separator after has been
+ # seen.
+ last_fs = "";
+ # Whether the last field separator was intended to be output.
+ last_fs_print = 0;
+
+ # rcu_batches stores the initialization for each instance of struct
+ # rcu_batch
+
+ in_comment = 0;
+
+ outputfile = "";
+}
+
+{
+ prev_outputfile = outputfile;
+ if (FILENAME ~ /\.h$/) {
+ outputfile = h_output;
+ if (FNR != NR) {
+ print "Incorrect file order" > "/dev/stderr";
+ exit 1;
+ }
+ }
+ else
+ outputfile = c_output;
+
+ if (prev_outputfile && outputfile != prev_outputfile) {
+ new_outputfile = outputfile;
+ outputfile = prev_outputfile;
+ update_fieldsep("", 0);
+ outputfile = new_outputfile;
+ }
+}
+
+# Combine the next line into $0.
+function combine_line() {
+ ret = getline next_line;
+ if (ret == 0) {
+ # Don't allow two consecutive getlines at the end of the file
+ if (eof_found) {
+ print "Error: expected more input." > "/dev/stderr";
+ exit 1;
+ } else {
+ eof_found = 1;
+ }
+ } else if (ret == -1) {
+ print "Error reading next line of file" FILENAME > "/dev/stderr";
+ exit 1;
+ }
+ $0 = $0 "\n" next_line;
+}
+
+# Combine backslashed lines and multiline comments.
+function combine_backslashes() {
+ while (/\\$|\/\*([^*]|\*+[^*\/])*\**$/) {
+ combine_line();
+ }
+}
+
+function read_line() {
+ combine_line();
+ combine_backslashes();
+}
+
+# Print out field separators and update variables that depend on them. Only
+# print if p is true. Call with sep="" and p=0 to print out the last field
+# separator.
+function update_fieldsep(sep, p) {
+ # Count braces
+ sep_tmp = sep;
+ gsub(quote_regexp "|" comment_regexp, "", sep_tmp);
+ while (1)
+ {
+ if (sub("[^{}()]*\\{", "", sep_tmp)) {
+ brace_nesting++;
+ continue;
+ }
+ if (sub("[^{}()]*\\}", "", sep_tmp)) {
+ brace_nesting--;
+ if (brace_nesting < 0) {
+ print "Unbalanced braces!" > "/dev/stderr";
+ exit 1;
+ }
+ continue;
+ }
+ if (sub("[^{}()]*\\(", "", sep_tmp)) {
+ paren_nesting++;
+ continue;
+ }
+ if (sub("[^{}()]*\\)", "", sep_tmp)) {
+ paren_nesting--;
+ if (paren_nesting < 0) {
+ print "Unbalanced parenthesis!" > "/dev/stderr";
+ exit 1;
+ }
+ continue;
+ }
+
+ break;
+ }
+
+ if (last_fs_print)
+ printf("%s", last_fs) > outputfile;
+ last_fs = sep;
+ last_fs_print = p;
+}
+
+# Shifts the fields down by n positions. Calls next if there are no more. If p
+# is true then print out field separators.
+function shift_fields(n, p) {
+ do {
+ if (match($0, FS) > 0) {
+ update_fieldsep(substr($0, RSTART, RLENGTH), p);
+ if (RSTART + RLENGTH <= length())
+ $0 = substr($0, RSTART + RLENGTH);
+ else
+ $0 = "";
+ } else {
+ update_fieldsep("", 0);
+ print "" > outputfile;
+ next;
+ }
+ } while (--n > 0);
+}
+
+# Shifts and prints the first n fields.
+function print_fields(n) {
+ do {
+ update_fieldsep("", 0);
+ printf("%s", $1) > outputfile;
+ shift_fields(1, 1);
+ } while (--n > 0);
+}
+
+{
+ combine_backslashes();
+}
+
+# Print leading FS
+{
+ if (match($0, "^(" FS ")+") > 0) {
+ update_fieldsep(substr($0, RSTART, RLENGTH), 1);
+ if (RSTART + RLENGTH <= length())
+ $0 = substr($0, RSTART + RLENGTH);
+ else
+ $0 = "";
+ }
+}
+
+# Parse the line.
+{
+ while (NF > 0) {
+ if ($1 == "struct" && NF < 3) {
+ read_line();
+ continue;
+ }
+
+ if (FILENAME ~ /\.h$/ && !inside_srcu_struct &&
+ brace_nesting == 0 && paren_nesting == 0 &&
+ $1 == "struct" && $2 == "srcu_struct" &&
+ $0 ~ "^struct(" FS ")+srcu_struct(" FS ")+\\{") {
+ inside_srcu_struct = 1;
+ print_fields(2);
+ continue;
+ }
+ if (inside_srcu_struct && brace_nesting == 0 &&
+ paren_nesting == 0) {
+ inside_srcu_struct = 0;
+ update_fieldsep("", 0);
+ for (name in rcu_batches)
+ print "extern struct rcu_batch " name ";" > outputfile;
+ }
+
+ if (inside_srcu_struct && $1 == "struct" && $2 == "rcu_batch") {
+ # Move rcu_batches outside of the struct.
+ rcu_batches[$3] = "";
+ shift_fields(3, 1);
+ sub(/;[[:space:]]*$/, "", last_fs);
+ continue;
+ }
+
+ if (FILENAME ~ /\.h$/ && !inside_srcu_init_def &&
+ $1 == "#define" && $2 == "__SRCU_STRUCT_INIT") {
+ inside_srcu_init_def = 1;
+ srcu_init_param_name = $3;
+ in_macro = 1;
+ print_fields(3);
+ continue;
+ }
+ if (inside_srcu_init_def && brace_nesting == 0 &&
+ paren_nesting == 0) {
+ inside_srcu_init_def = 0;
+ in_macro = 0;
+ continue;
+ }
+
+ if (inside_srcu_init_def && brace_nesting == 1 &&
+ paren_nesting == 0 && last_fs ~ /\.[[:space:]]*$/ &&
+ $1 ~ /^[[:alnum:]_]+$/) {
+ name = $1;
+ if (name in rcu_batches) {
+ # Remove the dot.
+ sub(/\.[[:space:]]*$/, "", last_fs);
+
+ old_record = $0;
+ do
+ shift_fields(1, 0);
+ while (last_fs !~ /,/ || paren_nesting > 0);
+ end_loc = length(old_record) - length($0);
+ end_loc += index(last_fs, ",") - length(last_fs);
+
+ last_fs = substr(last_fs, index(last_fs, ",") + 1);
+ last_fs_print = 1;
+
+ match(old_record, "^"name"("FS")+=");
+ start_loc = RSTART + RLENGTH;
+
+ len = end_loc - start_loc;
+ initializer = substr(old_record, start_loc, len);
+ gsub(srcu_init_param_name "\\.", "", initializer);
+ rcu_batches[name] = initializer;
+ continue;
+ }
+ }
+
+ # Don't include a nonexistent file
+ if (!in_macro && $1 == "#include" && /^#include[[:space:]]+"rcu\.h"/) {
+ update_fieldsep("", 0);
+ next;
+ }
+
+ # Ignore most preprocessor stuff.
+ if (!in_macro && $1 ~ /#/) {
+ break;
+ }
+
+ if (brace_nesting > 0 && $1 ~ "^[[:alnum:]_]+$" && NF < 2) {
+ read_line();
+ continue;
+ }
+ if (brace_nesting > 0 &&
+ $0 ~ "^[[:alnum:]_]+[[:space:]]*(\\.|->)[[:space:]]*[[:alnum:]_]+" &&
+ $2 in rcu_batches) {
+ # Make uses of rcu_batches global. Somewhat unreliable.
+ shift_fields(1, 0);
+ print_fields(1);
+ continue;
+ }
+
+ if ($1 == "static" && NF < 3) {
+ read_line();
+ continue;
+ }
+ if ($1 == "static" && ($2 == "bool" && $3 == "try_check_zero" ||
+ $2 == "void" && $3 == "srcu_flip")) {
+ shift_fields(1, 1);
+ print_fields(2);
+ continue;
+ }
+
+ # Distinguish between read-side and write-side memory barriers.
+ if ($1 == "smp_mb" && NF < 2) {
+ read_line();
+ continue;
+ }
+ if (match($0, /^smp_mb[[:space:]();\/*]*[[:alnum:]]/)) {
+ barrier_letter = substr($0, RLENGTH, 1);
+ if (barrier_letter ~ /A|D/)
+ new_barrier_name = "sync_smp_mb";
+ else if (barrier_letter ~ /B|C/)
+ new_barrier_name = "rs_smp_mb";
+ else {
+ print "Unrecognized memory barrier." > "/dev/null";
+ exit 1;
+ }
+
+ shift_fields(1, 1);
+ printf("%s", new_barrier_name) > outputfile;
+ continue;
+ }
+
+ # Skip definition of rcu_synchronize, since it is already
+ # defined in misc.h. Only present in old versions of srcu.
+ if (brace_nesting == 0 && paren_nesting == 0 &&
+ $1 == "struct" && $2 == "rcu_synchronize" &&
+ $0 ~ "^struct(" FS ")+rcu_synchronize(" FS ")+\\{") {
+ shift_fields(2, 0);
+ while (brace_nesting) {
+ if (NF < 2)
+ read_line();
+ shift_fields(1, 0);
+ }
+ }
+
+ # Skip definition of wakeme_after_rcu for the same reason
+ if (brace_nesting == 0 && $1 == "static" && $2 == "void" &&
+ $3 == "wakeme_after_rcu") {
+ while (NF < 5)
+ read_line();
+ shift_fields(3, 0);
+ do {
+ while (NF < 3)
+ read_line();
+ shift_fields(1, 0);
+ } while (paren_nesting || brace_nesting);
+ }
+
+ if ($1 ~ /^(unsigned|long)$/ && NF < 3) {
+ read_line();
+ continue;
+ }
+
+ # Give srcu_batches_completed the correct type for old SRCU.
+ if (brace_nesting == 0 && $1 == "long" &&
+ $2 == "srcu_batches_completed") {
+ update_fieldsep("", 0);
+ printf("unsigned ") > outputfile;
+ print_fields(2);
+ continue;
+ }
+ if (brace_nesting == 0 && $1 == "unsigned" && $2 == "long" &&
+ $3 == "srcu_batches_completed") {
+ print_fields(3);
+ continue;
+ }
+
+ # Just print out the input code by default.
+ print_fields(1);
+ }
+ update_fieldsep("", 0);
+ print > outputfile;
+ next;
+}
+
+END {
+ update_fieldsep("", 0);
+
+ if (brace_nesting != 0) {
+ print "Unbalanced braces!" > "/dev/stderr";
+ exit 1;
+ }
+
+ # Define the rcu_batches
+ for (name in rcu_batches)
+ print "struct rcu_batch " name " = " rcu_batches[name] ";" > c_output;
+}
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/assume.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/assume.h
new file mode 100644
index 000000000000..a64955447995
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/assume.h
@@ -0,0 +1,16 @@
+#ifndef ASSUME_H
+#define ASSUME_H
+
+/* Provide an assumption macro that can be disabled for gcc. */
+#ifdef RUN
+#define assume(x) \
+ do { \
+ /* Evaluate x to suppress warnings. */ \
+ (void) (x); \
+ } while (0)
+
+#else
+#define assume(x) __CPROVER_assume(x)
+#endif
+
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/barriers.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/barriers.h
new file mode 100644
index 000000000000..6687acc08e6d
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/barriers.h
@@ -0,0 +1,41 @@
+#ifndef BARRIERS_H
+#define BARRIERS_H
+
+#define barrier() __asm__ __volatile__("" : : : "memory")
+
+#ifdef RUN
+#define smp_mb() __sync_synchronize()
+#define smp_mb__after_unlock_lock() __sync_synchronize()
+#else
+/*
+ * Copied from CBMC's implementation of __sync_synchronize(), which
+ * seems to be disabled by default.
+ */
+#define smp_mb() __CPROVER_fence("WWfence", "RRfence", "RWfence", "WRfence", \
+ "WWcumul", "RRcumul", "RWcumul", "WRcumul")
+#define smp_mb__after_unlock_lock() __CPROVER_fence("WWfence", "RRfence", "RWfence", "WRfence", \
+ "WWcumul", "RRcumul", "RWcumul", "WRcumul")
+#endif
+
+/*
+ * Allow memory barriers to be disabled in either the read or write side
+ * of SRCU individually.
+ */
+
+#ifndef NO_SYNC_SMP_MB
+#define sync_smp_mb() smp_mb()
+#else
+#define sync_smp_mb() do {} while (0)
+#endif
+
+#ifndef NO_READ_SIDE_SMP_MB
+#define rs_smp_mb() smp_mb()
+#else
+#define rs_smp_mb() do {} while (0)
+#endif
+
+#define ACCESS_ONCE(x) (*(volatile typeof(x) *) &(x))
+#define READ_ONCE(x) ACCESS_ONCE(x)
+#define WRITE_ONCE(x, val) (ACCESS_ONCE(x) = (val))
+
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/bug_on.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/bug_on.h
new file mode 100644
index 000000000000..2a80e91f78e7
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/bug_on.h
@@ -0,0 +1,13 @@
+#ifndef BUG_ON_H
+#define BUG_ON_H
+
+#include <assert.h>
+
+#define BUG() assert(0)
+#define BUG_ON(x) assert(!(x))
+
+/* Does it make sense to treat warnings as errors? */
+#define WARN() BUG()
+#define WARN_ON(x) (BUG_ON(x), false)
+
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/combined_source.c b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/combined_source.c
new file mode 100644
index 000000000000..29eb5d2697ed
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/combined_source.c
@@ -0,0 +1,13 @@
+#include <config.h>
+
+/* Include all source files. */
+
+#include "include_srcu.c"
+
+#include "preempt.c"
+#include "misc.c"
+
+/* Used by test.c files */
+#include <pthread.h>
+#include <stdlib.h>
+#include <linux/srcu.h>
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/config.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/config.h
new file mode 100644
index 000000000000..a60038aeea7a
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/config.h
@@ -0,0 +1,27 @@
+/* "Cheater" definitions based on restricted Kconfig choices. */
+
+#undef CONFIG_TINY_RCU
+#undef __CHECKER__
+#undef CONFIG_DEBUG_LOCK_ALLOC
+#undef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+#undef CONFIG_HOTPLUG_CPU
+#undef CONFIG_MODULES
+#undef CONFIG_NO_HZ_FULL_SYSIDLE
+#undef CONFIG_PREEMPT_COUNT
+#undef CONFIG_PREEMPT_RCU
+#undef CONFIG_PROVE_RCU
+#undef CONFIG_RCU_NOCB_CPU
+#undef CONFIG_RCU_NOCB_CPU_ALL
+#undef CONFIG_RCU_STALL_COMMON
+#undef CONFIG_RCU_TRACE
+#undef CONFIG_RCU_USER_QS
+#undef CONFIG_TASKS_RCU
+#define CONFIG_TREE_RCU
+
+#define CONFIG_GENERIC_ATOMIC64
+
+#if NR_CPUS > 1
+#define CONFIG_SMP
+#else
+#undef CONFIG_SMP
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/include_srcu.c b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/include_srcu.c
new file mode 100644
index 000000000000..5ec582a53018
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/include_srcu.c
@@ -0,0 +1,31 @@
+#include <config.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include "int_typedefs.h"
+
+#include "barriers.h"
+#include "bug_on.h"
+#include "locks.h"
+#include "misc.h"
+#include "preempt.h"
+#include "percpu.h"
+#include "workqueues.h"
+
+#ifdef USE_SIMPLE_SYNC_SRCU
+#define synchronize_srcu(sp) synchronize_srcu_original(sp)
+#endif
+
+#include <srcu.c>
+
+#ifdef USE_SIMPLE_SYNC_SRCU
+#undef synchronize_srcu
+
+#include "simple_sync_srcu.c"
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/int_typedefs.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/int_typedefs.h
new file mode 100644
index 000000000000..3aad63917858
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/int_typedefs.h
@@ -0,0 +1,33 @@
+#ifndef INT_TYPEDEFS_H
+#define INT_TYPEDEFS_H
+
+#include <inttypes.h>
+
+typedef int8_t s8;
+typedef uint8_t u8;
+typedef int16_t s16;
+typedef uint16_t u16;
+typedef int32_t s32;
+typedef uint32_t u32;
+typedef int64_t s64;
+typedef uint64_t u64;
+
+typedef int8_t __s8;
+typedef uint8_t __u8;
+typedef int16_t __s16;
+typedef uint16_t __u16;
+typedef int32_t __s32;
+typedef uint32_t __u32;
+typedef int64_t __s64;
+typedef uint64_t __u64;
+
+#define S8_C(x) INT8_C(x)
+#define U8_C(x) UINT8_C(x)
+#define S16_C(x) INT16_C(x)
+#define U16_C(x) UINT16_C(x)
+#define S32_C(x) INT32_C(x)
+#define U32_C(x) UINT32_C(x)
+#define S64_C(x) INT64_C(x)
+#define U64_C(x) UINT64_C(x)
+
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/locks.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/locks.h
new file mode 100644
index 000000000000..356004665576
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/locks.h
@@ -0,0 +1,220 @@
+#ifndef LOCKS_H
+#define LOCKS_H
+
+#include <limits.h>
+#include <pthread.h>
+#include <stdbool.h>
+
+#include "assume.h"
+#include "bug_on.h"
+#include "preempt.h"
+
+int nondet_int(void);
+
+#define __acquire(x)
+#define __acquires(x)
+#define __release(x)
+#define __releases(x)
+
+/* Only use one lock mechanism. Select which one. */
+#ifdef PTHREAD_LOCK
+struct lock_impl {
+ pthread_mutex_t mutex;
+};
+
+static inline void lock_impl_lock(struct lock_impl *lock)
+{
+ BUG_ON(pthread_mutex_lock(&lock->mutex));
+}
+
+static inline void lock_impl_unlock(struct lock_impl *lock)
+{
+ BUG_ON(pthread_mutex_unlock(&lock->mutex));
+}
+
+static inline bool lock_impl_trylock(struct lock_impl *lock)
+{
+ int err = pthread_mutex_trylock(&lock->mutex);
+
+ if (!err)
+ return true;
+ else if (err == EBUSY)
+ return false;
+ BUG();
+}
+
+static inline void lock_impl_init(struct lock_impl *lock)
+{
+ pthread_mutex_init(&lock->mutex, NULL);
+}
+
+#define LOCK_IMPL_INITIALIZER {.mutex = PTHREAD_MUTEX_INITIALIZER}
+
+#else /* !defined(PTHREAD_LOCK) */
+/* Spinlock that assumes that it always gets the lock immediately. */
+
+struct lock_impl {
+ bool locked;
+};
+
+static inline bool lock_impl_trylock(struct lock_impl *lock)
+{
+#ifdef RUN
+ /* TODO: Should this be a test and set? */
+ return __sync_bool_compare_and_swap(&lock->locked, false, true);
+#else
+ __CPROVER_atomic_begin();
+ bool old_locked = lock->locked;
+ lock->locked = true;
+ __CPROVER_atomic_end();
+
+ /* Minimal barrier to prevent accesses leaking out of lock. */
+ __CPROVER_fence("RRfence", "RWfence");
+
+ return !old_locked;
+#endif
+}
+
+static inline void lock_impl_lock(struct lock_impl *lock)
+{
+ /*
+ * CBMC doesn't support busy waiting, so just assume that the
+ * lock is available.
+ */
+ assume(lock_impl_trylock(lock));
+
+ /*
+ * If the lock was already held by this thread then the assumption
+ * is unsatisfiable (deadlock).
+ */
+}
+
+static inline void lock_impl_unlock(struct lock_impl *lock)
+{
+#ifdef RUN
+ BUG_ON(!__sync_bool_compare_and_swap(&lock->locked, true, false));
+#else
+ /* Minimal barrier to prevent accesses leaking out of lock. */
+ __CPROVER_fence("RWfence", "WWfence");
+
+ __CPROVER_atomic_begin();
+ bool old_locked = lock->locked;
+ lock->locked = false;
+ __CPROVER_atomic_end();
+
+ BUG_ON(!old_locked);
+#endif
+}
+
+static inline void lock_impl_init(struct lock_impl *lock)
+{
+ lock->locked = false;
+}
+
+#define LOCK_IMPL_INITIALIZER {.locked = false}
+
+#endif /* !defined(PTHREAD_LOCK) */
+
+/*
+ * Implement spinlocks using the lock mechanism. Wrap the lock to prevent mixing
+ * locks of different types.
+ */
+typedef struct {
+ struct lock_impl internal_lock;
+} spinlock_t;
+
+#define SPIN_LOCK_UNLOCKED {.internal_lock = LOCK_IMPL_INITIALIZER}
+#define __SPIN_LOCK_UNLOCKED(x) SPIN_LOCK_UNLOCKED
+#define DEFINE_SPINLOCK(x) spinlock_t x = SPIN_LOCK_UNLOCKED
+
+static inline void spin_lock_init(spinlock_t *lock)
+{
+ lock_impl_init(&lock->internal_lock);
+}
+
+static inline void spin_lock(spinlock_t *lock)
+{
+ /*
+ * Spin locks also need to be removed in order to eliminate all
+ * memory barriers. They are only used by the write side anyway.
+ */
+#ifndef NO_SYNC_SMP_MB
+ preempt_disable();
+ lock_impl_lock(&lock->internal_lock);
+#endif
+}
+
+static inline void spin_unlock(spinlock_t *lock)
+{
+#ifndef NO_SYNC_SMP_MB
+ lock_impl_unlock(&lock->internal_lock);
+ preempt_enable();
+#endif
+}
+
+/* Don't bother with interrupts */
+#define spin_lock_irq(lock) spin_lock(lock)
+#define spin_unlock_irq(lock) spin_unlock(lock)
+#define spin_lock_irqsave(lock, flags) spin_lock(lock)
+#define spin_unlock_irqrestore(lock, flags) spin_unlock(lock)
+
+/*
+ * This is supposed to return an int, but I think that a bool should work as
+ * well.
+ */
+static inline bool spin_trylock(spinlock_t *lock)
+{
+#ifndef NO_SYNC_SMP_MB
+ preempt_disable();
+ return lock_impl_trylock(&lock->internal_lock);
+#else
+ return true;
+#endif
+}
+
+struct completion {
+ /* Hopefuly this won't overflow. */
+ unsigned int count;
+};
+
+#define COMPLETION_INITIALIZER(x) {.count = 0}
+#define DECLARE_COMPLETION(x) struct completion x = COMPLETION_INITIALIZER(x)
+#define DECLARE_COMPLETION_ONSTACK(x) DECLARE_COMPLETION(x)
+
+static inline void init_completion(struct completion *c)
+{
+ c->count = 0;
+}
+
+static inline void wait_for_completion(struct completion *c)
+{
+ unsigned int prev_count = __sync_fetch_and_sub(&c->count, 1);
+
+ assume(prev_count);
+}
+
+static inline void complete(struct completion *c)
+{
+ unsigned int prev_count = __sync_fetch_and_add(&c->count, 1);
+
+ BUG_ON(prev_count == UINT_MAX);
+}
+
+/* This function probably isn't very useful for CBMC. */
+static inline bool try_wait_for_completion(struct completion *c)
+{
+ BUG();
+}
+
+static inline bool completion_done(struct completion *c)
+{
+ return c->count;
+}
+
+/* TODO: Implement complete_all */
+static inline void complete_all(struct completion *c)
+{
+ BUG();
+}
+
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/misc.c b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/misc.c
new file mode 100644
index 000000000000..ca892e3b2351
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/misc.c
@@ -0,0 +1,11 @@
+#include <config.h>
+
+#include "misc.h"
+#include "bug_on.h"
+
+struct rcu_head;
+
+void wakeme_after_rcu(struct rcu_head *head)
+{
+ BUG();
+}
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/misc.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/misc.h
new file mode 100644
index 000000000000..aca50030f954
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/misc.h
@@ -0,0 +1,58 @@
+#ifndef MISC_H
+#define MISC_H
+
+#include "assume.h"
+#include "int_typedefs.h"
+#include "locks.h"
+
+#include <linux/types.h>
+
+/* Probably won't need to deal with bottom halves. */
+static inline void local_bh_disable(void) {}
+static inline void local_bh_enable(void) {}
+
+#define MODULE_ALIAS(X)
+#define module_param(...)
+#define EXPORT_SYMBOL_GPL(x)
+
+#define container_of(ptr, type, member) ({ \
+ const typeof(((type *)0)->member) *__mptr = (ptr); \
+ (type *)((char *)__mptr - offsetof(type, member)); \
+})
+
+#ifndef USE_SIMPLE_SYNC_SRCU
+/* Abuse udelay to make sure that busy loops terminate. */
+#define udelay(x) assume(0)
+
+#else
+
+/* The simple custom synchronize_srcu is ok with try_check_zero failing. */
+#define udelay(x) do { } while (0)
+#endif
+
+#define trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
+ do { } while (0)
+
+#define notrace
+
+/* Avoid including rcupdate.h */
+struct rcu_synchronize {
+ struct rcu_head head;
+ struct completion completion;
+};
+
+void wakeme_after_rcu(struct rcu_head *head);
+
+#define rcu_lock_acquire(a) do { } while (0)
+#define rcu_lock_release(a) do { } while (0)
+#define rcu_lockdep_assert(c, s) do { } while (0)
+#define RCU_LOCKDEP_WARN(c, s) do { } while (0)
+
+/* Let CBMC non-deterministically choose switch between normal and expedited. */
+bool rcu_gp_is_normal(void);
+bool rcu_gp_is_expedited(void);
+
+/* Do the same for old versions of rcu. */
+#define rcu_expedited (rcu_gp_is_expedited())
+
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/percpu.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/percpu.h
new file mode 100644
index 000000000000..3de5a49de49b
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/percpu.h
@@ -0,0 +1,92 @@
+#ifndef PERCPU_H
+#define PERCPU_H
+
+#include <stddef.h>
+#include "bug_on.h"
+#include "preempt.h"
+
+#define __percpu
+
+/* Maximum size of any percpu data. */
+#define PERCPU_OFFSET (4 * sizeof(long))
+
+/* Ignore alignment, as CBMC doesn't care about false sharing. */
+#define alloc_percpu(type) __alloc_percpu(sizeof(type), 1)
+
+static inline void *__alloc_percpu(size_t size, size_t align)
+{
+ BUG();
+ return NULL;
+}
+
+static inline void free_percpu(void *ptr)
+{
+ BUG();
+}
+
+#define per_cpu_ptr(ptr, cpu) \
+ ((typeof(ptr)) ((char *) (ptr) + PERCPU_OFFSET * cpu))
+
+#define __this_cpu_inc(pcp) __this_cpu_add(pcp, 1)
+#define __this_cpu_dec(pcp) __this_cpu_sub(pcp, 1)
+#define __this_cpu_sub(pcp, n) __this_cpu_add(pcp, -(typeof(pcp)) (n))
+
+#define this_cpu_inc(pcp) this_cpu_add(pcp, 1)
+#define this_cpu_dec(pcp) this_cpu_sub(pcp, 1)
+#define this_cpu_sub(pcp, n) this_cpu_add(pcp, -(typeof(pcp)) (n))
+
+/* Make CBMC use atomics to work around bug. */
+#ifdef RUN
+#define THIS_CPU_ADD_HELPER(ptr, x) (*(ptr) += (x))
+#else
+/*
+ * Split the atomic into a read and a write so that it has the least
+ * possible ordering.
+ */
+#define THIS_CPU_ADD_HELPER(ptr, x) \
+ do { \
+ typeof(ptr) this_cpu_add_helper_ptr = (ptr); \
+ typeof(ptr) this_cpu_add_helper_x = (x); \
+ typeof(*ptr) this_cpu_add_helper_temp; \
+ __CPROVER_atomic_begin(); \
+ this_cpu_add_helper_temp = *(this_cpu_add_helper_ptr); \
+ __CPROVER_atomic_end(); \
+ this_cpu_add_helper_temp += this_cpu_add_helper_x; \
+ __CPROVER_atomic_begin(); \
+ *(this_cpu_add_helper_ptr) = this_cpu_add_helper_temp; \
+ __CPROVER_atomic_end(); \
+ } while (0)
+#endif
+
+/*
+ * For some reason CBMC needs an atomic operation even though this is percpu
+ * data.
+ */
+#define __this_cpu_add(pcp, n) \
+ do { \
+ BUG_ON(preemptible()); \
+ THIS_CPU_ADD_HELPER(per_cpu_ptr(&(pcp), thread_cpu_id), \
+ (typeof(pcp)) (n)); \
+ } while (0)
+
+#define this_cpu_add(pcp, n) \
+ do { \
+ int this_cpu_add_impl_cpu = get_cpu(); \
+ THIS_CPU_ADD_HELPER(per_cpu_ptr(&(pcp), this_cpu_add_impl_cpu), \
+ (typeof(pcp)) (n)); \
+ put_cpu(); \
+ } while (0)
+
+/*
+ * This will cause a compiler warning because of the cast from char[][] to
+ * type*. This will cause a compile time error if type is too big.
+ */
+#define DEFINE_PER_CPU(type, name) \
+ char name[NR_CPUS][PERCPU_OFFSET]; \
+ typedef char percpu_too_big_##name \
+ [sizeof(type) > PERCPU_OFFSET ? -1 : 1]
+
+#define for_each_possible_cpu(cpu) \
+ for ((cpu) = 0; (cpu) < NR_CPUS; ++(cpu))
+
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.c b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.c
new file mode 100644
index 000000000000..4f1b068e9b7a
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.c
@@ -0,0 +1,78 @@
+#include <config.h>
+
+#include "preempt.h"
+
+#include "assume.h"
+#include "locks.h"
+
+/* Support NR_CPUS of at most 64 */
+#define CPU_PREEMPTION_LOCKS_INIT0 LOCK_IMPL_INITIALIZER
+#define CPU_PREEMPTION_LOCKS_INIT1 \
+ CPU_PREEMPTION_LOCKS_INIT0, CPU_PREEMPTION_LOCKS_INIT0
+#define CPU_PREEMPTION_LOCKS_INIT2 \
+ CPU_PREEMPTION_LOCKS_INIT1, CPU_PREEMPTION_LOCKS_INIT1
+#define CPU_PREEMPTION_LOCKS_INIT3 \
+ CPU_PREEMPTION_LOCKS_INIT2, CPU_PREEMPTION_LOCKS_INIT2
+#define CPU_PREEMPTION_LOCKS_INIT4 \
+ CPU_PREEMPTION_LOCKS_INIT3, CPU_PREEMPTION_LOCKS_INIT3
+#define CPU_PREEMPTION_LOCKS_INIT5 \
+ CPU_PREEMPTION_LOCKS_INIT4, CPU_PREEMPTION_LOCKS_INIT4
+
+/*
+ * Simulate disabling preemption by locking a particular cpu. NR_CPUS
+ * should be the actual number of cpus, not just the maximum.
+ */
+struct lock_impl cpu_preemption_locks[NR_CPUS] = {
+ CPU_PREEMPTION_LOCKS_INIT0
+#if (NR_CPUS - 1) & 1
+ , CPU_PREEMPTION_LOCKS_INIT0
+#endif
+#if (NR_CPUS - 1) & 2
+ , CPU_PREEMPTION_LOCKS_INIT1
+#endif
+#if (NR_CPUS - 1) & 4
+ , CPU_PREEMPTION_LOCKS_INIT2
+#endif
+#if (NR_CPUS - 1) & 8
+ , CPU_PREEMPTION_LOCKS_INIT3
+#endif
+#if (NR_CPUS - 1) & 16
+ , CPU_PREEMPTION_LOCKS_INIT4
+#endif
+#if (NR_CPUS - 1) & 32
+ , CPU_PREEMPTION_LOCKS_INIT5
+#endif
+};
+
+#undef CPU_PREEMPTION_LOCKS_INIT0
+#undef CPU_PREEMPTION_LOCKS_INIT1
+#undef CPU_PREEMPTION_LOCKS_INIT2
+#undef CPU_PREEMPTION_LOCKS_INIT3
+#undef CPU_PREEMPTION_LOCKS_INIT4
+#undef CPU_PREEMPTION_LOCKS_INIT5
+
+__thread int thread_cpu_id;
+__thread int preempt_disable_count;
+
+void preempt_disable(void)
+{
+ BUG_ON(preempt_disable_count < 0 || preempt_disable_count == INT_MAX);
+
+ if (preempt_disable_count++)
+ return;
+
+ thread_cpu_id = nondet_int();
+ assume(thread_cpu_id >= 0);
+ assume(thread_cpu_id < NR_CPUS);
+ lock_impl_lock(&cpu_preemption_locks[thread_cpu_id]);
+}
+
+void preempt_enable(void)
+{
+ BUG_ON(preempt_disable_count < 1);
+
+ if (--preempt_disable_count)
+ return;
+
+ lock_impl_unlock(&cpu_preemption_locks[thread_cpu_id]);
+}
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.h
new file mode 100644
index 000000000000..2f95ee0e4dd5
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/preempt.h
@@ -0,0 +1,58 @@
+#ifndef PREEMPT_H
+#define PREEMPT_H
+
+#include <stdbool.h>
+
+#include "bug_on.h"
+
+/* This flag contains garbage if preempt_disable_count is 0. */
+extern __thread int thread_cpu_id;
+
+/* Support recursive preemption disabling. */
+extern __thread int preempt_disable_count;
+
+void preempt_disable(void);
+void preempt_enable(void);
+
+static inline void preempt_disable_notrace(void)
+{
+ preempt_disable();
+}
+
+static inline void preempt_enable_no_resched(void)
+{
+ preempt_enable();
+}
+
+static inline void preempt_enable_notrace(void)
+{
+ preempt_enable();
+}
+
+static inline int preempt_count(void)
+{
+ return preempt_disable_count;
+}
+
+static inline bool preemptible(void)
+{
+ return !preempt_count();
+}
+
+static inline int get_cpu(void)
+{
+ preempt_disable();
+ return thread_cpu_id;
+}
+
+static inline void put_cpu(void)
+{
+ preempt_enable();
+}
+
+static inline void might_sleep(void)
+{
+ BUG_ON(preempt_disable_count);
+}
+
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/simple_sync_srcu.c b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/simple_sync_srcu.c
new file mode 100644
index 000000000000..ac9cbc62b411
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/simple_sync_srcu.c
@@ -0,0 +1,50 @@
+#include <config.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include "int_typedefs.h"
+
+#include "barriers.h"
+#include "bug_on.h"
+#include "locks.h"
+#include "misc.h"
+#include "preempt.h"
+#include "percpu.h"
+#include "workqueues.h"
+
+#include <linux/srcu.h>
+
+/* Functions needed from modify_srcu.c */
+bool try_check_zero(struct srcu_struct *sp, int idx, int trycount);
+void srcu_flip(struct srcu_struct *sp);
+
+/* Simpler implementation of synchronize_srcu that ignores batching. */
+void synchronize_srcu(struct srcu_struct *sp)
+{
+ int idx;
+ /*
+ * This code assumes that try_check_zero will succeed anyway,
+ * so there is no point in multiple tries.
+ */
+ const int trycount = 1;
+
+ might_sleep();
+
+ /* Ignore the lock, as multiple writers aren't working yet anyway. */
+
+ idx = 1 ^ (sp->completed & 1);
+
+ /* For comments see srcu_advance_batches. */
+
+ assume(try_check_zero(sp, idx, trycount));
+
+ srcu_flip(sp);
+
+ assume(try_check_zero(sp, idx^1, trycount));
+}
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/workqueues.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/workqueues.h
new file mode 100644
index 000000000000..e58c8dfd3e90
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/workqueues.h
@@ -0,0 +1,102 @@
+#ifndef WORKQUEUES_H
+#define WORKQUEUES_H
+
+#include <stdbool.h>
+
+#include "barriers.h"
+#include "bug_on.h"
+#include "int_typedefs.h"
+
+#include <linux/types.h>
+
+/* Stub workqueue implementation. */
+
+struct work_struct;
+typedef void (*work_func_t)(struct work_struct *work);
+void delayed_work_timer_fn(unsigned long __data);
+
+struct work_struct {
+/* atomic_long_t data; */
+ unsigned long data;
+
+ struct list_head entry;
+ work_func_t func;
+#ifdef CONFIG_LOCKDEP
+ struct lockdep_map lockdep_map;
+#endif
+};
+
+struct timer_list {
+ struct hlist_node entry;
+ unsigned long expires;
+ void (*function)(unsigned long);
+ unsigned long data;
+ u32 flags;
+ int slack;
+};
+
+struct delayed_work {
+ struct work_struct work;
+ struct timer_list timer;
+
+ /* target workqueue and CPU ->timer uses to queue ->work */
+ struct workqueue_struct *wq;
+ int cpu;
+};
+
+
+static inline bool schedule_work(struct work_struct *work)
+{
+ BUG();
+ return true;
+}
+
+static inline bool schedule_work_on(int cpu, struct work_struct *work)
+{
+ BUG();
+ return true;
+}
+
+static inline bool queue_work(struct workqueue_struct *wq,
+ struct work_struct *work)
+{
+ BUG();
+ return true;
+}
+
+static inline bool queue_delayed_work(struct workqueue_struct *wq,
+ struct delayed_work *dwork,
+ unsigned long delay)
+{
+ BUG();
+ return true;
+}
+
+#define INIT_WORK(w, f) \
+ do { \
+ (w)->data = 0; \
+ (w)->func = (f); \
+ } while (0)
+
+#define INIT_DELAYED_WORK(w, f) INIT_WORK(&(w)->work, (f))
+
+#define __WORK_INITIALIZER(n, f) { \
+ .data = 0, \
+ .entry = { &(n).entry, &(n).entry }, \
+ .func = f \
+ }
+
+/* Don't bother initializing timer. */
+#define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
+ .work = __WORK_INITIALIZER((n).work, (f)), \
+ }
+
+#define DECLARE_WORK(n, f) \
+ struct workqueue_struct n = __WORK_INITIALIZER
+
+#define DECLARE_DELAYED_WORK(n, f) \
+ struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
+
+#define system_power_efficient_wq ((struct workqueue_struct *) NULL)
+
+#endif
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/.gitignore b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/.gitignore
new file mode 100644
index 000000000000..f47cb2045f13
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/.gitignore
@@ -0,0 +1 @@
+*.out
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/Makefile b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/Makefile
new file mode 100644
index 000000000000..3a3aee149225
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/Makefile
@@ -0,0 +1,11 @@
+CBMC_FLAGS = -I../.. -I../../src -I../../include -I../../empty_includes -32 -pointer-check -mm pso
+
+all:
+ for i in ./*.pass; do \
+ echo $$i ; \
+ CBMC_FLAGS="$(CBMC_FLAGS)" sh ../test_script.sh --should-pass $$i > $$i.out 2>&1 ; \
+ done
+ for i in ./*.fail; do \
+ echo $$i ; \
+ CBMC_FLAGS="$(CBMC_FLAGS)" sh ../test_script.sh --should-fail $$i > $$i.out 2>&1 ; \
+ done
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/assert_end.fail b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/assert_end.fail
new file mode 100644
index 000000000000..40c8075919d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/assert_end.fail
@@ -0,0 +1 @@
+test_cbmc_options="-DASSERT_END"
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force.fail b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force.fail
new file mode 100644
index 000000000000..ada5baf0b60d
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force.fail
@@ -0,0 +1 @@
+test_cbmc_options="-DFORCE_FAILURE"
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force2.fail b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force2.fail
new file mode 100644
index 000000000000..8fe00c8db466
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force2.fail
@@ -0,0 +1 @@
+test_cbmc_options="-DFORCE_FAILURE_2"
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force3.fail b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force3.fail
new file mode 100644
index 000000000000..612ed6772844
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/force3.fail
@@ -0,0 +1 @@
+test_cbmc_options="-DFORCE_FAILURE_3"
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/main.pass b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/main.pass
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/main.pass
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/test.c b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/test.c
new file mode 100644
index 000000000000..470b1105a112
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/store_buffering/test.c
@@ -0,0 +1,72 @@
+#include <src/combined_source.c>
+
+int x;
+int y;
+
+int __unbuffered_tpr_x;
+int __unbuffered_tpr_y;
+
+DEFINE_SRCU(ss);
+
+void rcu_reader(void)
+{
+ int idx;
+
+#ifndef FORCE_FAILURE_3
+ idx = srcu_read_lock(&ss);
+#endif
+ might_sleep();
+
+ __unbuffered_tpr_y = READ_ONCE(y);
+#ifdef FORCE_FAILURE
+ srcu_read_unlock(&ss, idx);
+ idx = srcu_read_lock(&ss);
+#endif
+ WRITE_ONCE(x, 1);
+
+#ifndef FORCE_FAILURE_3
+ srcu_read_unlock(&ss, idx);
+#endif
+ might_sleep();
+}
+
+void *thread_update(void *arg)
+{
+ WRITE_ONCE(y, 1);
+#ifndef FORCE_FAILURE_2
+ synchronize_srcu(&ss);
+#endif
+ might_sleep();
+ __unbuffered_tpr_x = READ_ONCE(x);
+
+ return NULL;
+}
+
+void *thread_process_reader(void *arg)
+{
+ rcu_reader();
+
+ return NULL;
+}
+
+int main(int argc, char *argv[])
+{
+ pthread_t tu;
+ pthread_t tpr;
+
+ if (pthread_create(&tu, NULL, thread_update, NULL))
+ abort();
+ if (pthread_create(&tpr, NULL, thread_process_reader, NULL))
+ abort();
+ if (pthread_join(tu, NULL))
+ abort();
+ if (pthread_join(tpr, NULL))
+ abort();
+ assert(__unbuffered_tpr_y != 0 || __unbuffered_tpr_x != 0);
+
+#ifdef ASSERT_END
+ assert(0);
+#endif
+
+ return 0;
+}
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/test_script.sh b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/test_script.sh
new file mode 100755
index 000000000000..d1545972a0fa
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/tests/test_script.sh
@@ -0,0 +1,102 @@
+#!/bin/sh
+
+# This script expects a mode (either --should-pass or --should-fail) followed by
+# an input file. The script uses the following environment variables. The test C
+# source file is expected to be named test.c in the directory containing the
+# input file.
+#
+# CBMC: The command to run CBMC. Default: cbmc
+# CBMC_FLAGS: Additional flags to pass to CBMC
+# NR_CPUS: Number of cpus to run tests with. Default specified by the test
+# SYNC_SRCU_MODE: Choose implementation of synchronize_srcu. Defaults to simple.
+# kernel: Version included in the linux kernel source.
+# simple: Use try_check_zero directly.
+#
+# The input file is a script that is sourced by this file. It can define any of
+# the following variables to configure the test.
+#
+# test_cbmc_options: Extra options to pass to CBMC.
+# min_cpus_fail: Minimum number of CPUs (NR_CPUS) for verification to fail.
+# The test is expected to pass if it is run with fewer. (Only
+# useful for .fail files)
+# default_cpus: Quantity of CPUs to use for the test, if not specified on the
+# command line. Default: Larger of 2 and MIN_CPUS_FAIL.
+
+set -e
+
+if test "$#" -ne 2; then
+ echo "Expected one option followed by an input file" 1>&2
+ exit 99
+fi
+
+if test "x$1" = "x--should-pass"; then
+ should_pass="yes"
+elif test "x$1" = "x--should-fail"; then
+ should_pass="no"
+else
+ echo "Unrecognized argument '$1'" 1>&2
+
+ # Exit code 99 indicates a hard error.
+ exit 99
+fi
+
+CBMC=${CBMC:-cbmc}
+
+SYNC_SRCU_MODE=${SYNC_SRCU_MODE:-simple}
+
+case ${SYNC_SRCU_MODE} in
+kernel) sync_srcu_mode_flags="" ;;
+simple) sync_srcu_mode_flags="-DUSE_SIMPLE_SYNC_SRCU" ;;
+
+*)
+ echo "Unrecognized argument '${SYNC_SRCU_MODE}'" 1>&2
+ exit 99
+ ;;
+esac
+
+min_cpus_fail=1
+
+c_file=`dirname "$2"`/test.c
+
+# Source the input file.
+. $2
+
+if test ${min_cpus_fail} -gt 2; then
+ default_default_cpus=${min_cpus_fail}
+else
+ default_default_cpus=2
+fi
+default_cpus=${default_cpus:-${default_default_cpus}}
+cpus=${NR_CPUS:-${default_cpus}}
+
+# Check if there are two few cpus to make the test fail.
+if test $cpus -lt ${min_cpus_fail:-0}; then
+ should_pass="yes"
+fi
+
+cbmc_opts="-DNR_CPUS=${cpus} ${sync_srcu_mode_flags} ${test_cbmc_options} ${CBMC_FLAGS}"
+
+echo "Running CBMC: ${CBMC} ${cbmc_opts} ${c_file}"
+if ${CBMC} ${cbmc_opts} "${c_file}"; then
+ # Verification successful. Make sure that it was supposed to verify.
+ test "x${should_pass}" = xyes
+else
+ cbmc_exit_status=$?
+
+ # An exit status of 10 indicates a failed verification.
+ # (see cbmc_parse_optionst::do_bmc in the CBMC source code)
+ if test ${cbmc_exit_status} -eq 10 && test "x${should_pass}" = xno; then
+ :
+ else
+ echo "CBMC returned ${cbmc_exit_status} exit status" 1>&2
+
+ # Parse errors have exit status 6. Any other type of error
+ # should be considered a hard error.
+ if test ${cbmc_exit_status} -ne 6 && \
+ test ${cbmc_exit_status} -ne 10; then
+ exit 99
+ else
+ exit 1
+ fi
+ fi
+fi