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-rw-r--r--kernel/fork.c66
1 files changed, 44 insertions, 22 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index a60459947f18..fbe9dfcd8680 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -77,7 +77,6 @@
#include <linux/blkdev.h>
#include <linux/fs_struct.h>
#include <linux/magic.h>
-#include <linux/sched/mm.h>
#include <linux/perf_event.h>
#include <linux/posix-timers.h>
#include <linux/user-return-notifier.h>
@@ -217,6 +216,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
memset(s->addr, 0, THREAD_SIZE);
tsk->stack_vm_area = s;
+ tsk->stack = s->addr;
return s->addr;
}
@@ -428,7 +428,7 @@ static void release_task_stack(struct task_struct *tsk)
#ifdef CONFIG_THREAD_INFO_IN_TASK
void put_task_stack(struct task_struct *tsk)
{
- if (atomic_dec_and_test(&tsk->stack_refcount))
+ if (refcount_dec_and_test(&tsk->stack_refcount))
release_task_stack(tsk);
}
#endif
@@ -446,7 +446,7 @@ void free_task(struct task_struct *tsk)
* If the task had a separate stack allocation, it should be gone
* by now.
*/
- WARN_ON_ONCE(atomic_read(&tsk->stack_refcount) != 0);
+ WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0);
#endif
rt_mutex_debug_task_free(tsk);
ftrace_graph_exit_task(tsk);
@@ -709,14 +709,14 @@ static inline void free_signal_struct(struct signal_struct *sig)
static inline void put_signal_struct(struct signal_struct *sig)
{
- if (atomic_dec_and_test(&sig->sigcnt))
+ if (refcount_dec_and_test(&sig->sigcnt))
free_signal_struct(sig);
}
void __put_task_struct(struct task_struct *tsk)
{
WARN_ON(!tsk->exit_state);
- WARN_ON(atomic_read(&tsk->usage));
+ WARN_ON(refcount_read(&tsk->usage));
WARN_ON(tsk == current);
cgroup_free(tsk);
@@ -815,6 +815,7 @@ void __init fork_init(void)
#endif
lockdep_init_task(&init_task);
+ uprobes_init();
}
int __weak arch_dup_task_struct(struct task_struct *dst,
@@ -866,7 +867,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
tsk->stack_vm_area = stack_vm_area;
#endif
#ifdef CONFIG_THREAD_INFO_IN_TASK
- atomic_set(&tsk->stack_refcount, 1);
+ refcount_set(&tsk->stack_refcount, 1);
#endif
if (err)
@@ -895,7 +896,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
* One for us, one for whoever does the "release_task()" (usually
* parent)
*/
- atomic_set(&tsk->usage, 2);
+ refcount_set(&tsk->usage, 2);
#ifdef CONFIG_BLK_DEV_IO_TRACE
tsk->btrace_seq = 0;
#endif
@@ -980,7 +981,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
mm_pgtables_bytes_init(mm);
mm->map_count = 0;
mm->locked_vm = 0;
- mm->pinned_vm = 0;
+ atomic64_set(&mm->pinned_vm, 0);
memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
spin_lock_init(&mm->page_table_lock);
spin_lock_init(&mm->arg_lock);
@@ -1298,13 +1299,20 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
complete_vfork_done(tsk);
}
-/*
- * Allocate a new mm structure and copy contents from the
- * mm structure of the passed in task structure.
+/**
+ * dup_mm() - duplicates an existing mm structure
+ * @tsk: the task_struct with which the new mm will be associated.
+ * @oldmm: the mm to duplicate.
+ *
+ * Allocates a new mm structure and duplicates the provided @oldmm structure
+ * content into it.
+ *
+ * Return: the duplicated mm or NULL on failure.
*/
-static struct mm_struct *dup_mm(struct task_struct *tsk)
+static struct mm_struct *dup_mm(struct task_struct *tsk,
+ struct mm_struct *oldmm)
{
- struct mm_struct *mm, *oldmm = current->mm;
+ struct mm_struct *mm;
int err;
mm = allocate_mm();
@@ -1371,7 +1379,7 @@ static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
}
retval = -ENOMEM;
- mm = dup_mm(tsk);
+ mm = dup_mm(tsk, current->mm);
if (!mm)
goto fail_nomem;
@@ -1462,7 +1470,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
struct sighand_struct *sig;
if (clone_flags & CLONE_SIGHAND) {
- atomic_inc(&current->sighand->count);
+ refcount_inc(&current->sighand->count);
return 0;
}
sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
@@ -1470,7 +1478,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
if (!sig)
return -ENOMEM;
- atomic_set(&sig->count, 1);
+ refcount_set(&sig->count, 1);
spin_lock_irq(&current->sighand->siglock);
memcpy(sig->action, current->sighand->action, sizeof(sig->action));
spin_unlock_irq(&current->sighand->siglock);
@@ -1479,7 +1487,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
void __cleanup_sighand(struct sighand_struct *sighand)
{
- if (atomic_dec_and_test(&sighand->count)) {
+ if (refcount_dec_and_test(&sighand->count)) {
signalfd_cleanup(sighand);
/*
* sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it
@@ -1526,7 +1534,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
sig->nr_threads = 1;
atomic_set(&sig->live, 1);
- atomic_set(&sig->sigcnt, 1);
+ refcount_set(&sig->sigcnt, 1);
/* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */
sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node);
@@ -1833,8 +1841,6 @@ static __latent_entropy struct task_struct *copy_process(
posix_cpu_timers_init(p);
- p->start_time = ktime_get_ns();
- p->real_start_time = ktime_get_boot_ns();
p->io_context = NULL;
audit_set_context(p, NULL);
cgroup_fork(p);
@@ -2001,6 +2007,17 @@ static __latent_entropy struct task_struct *copy_process(
goto bad_fork_free_pid;
/*
+ * From this point on we must avoid any synchronous user-space
+ * communication until we take the tasklist-lock. In particular, we do
+ * not want user-space to be able to predict the process start-time by
+ * stalling fork(2) after we recorded the start_time but before it is
+ * visible to the system.
+ */
+
+ p->start_time = ktime_get_ns();
+ p->real_start_time = ktime_get_boot_ns();
+
+ /*
* Make it visible to the rest of the system, but dont wake it up yet.
* Need tasklist lock for parent etc handling!
*/
@@ -2072,7 +2089,7 @@ static __latent_entropy struct task_struct *copy_process(
} else {
current->signal->nr_threads++;
atomic_inc(&current->signal->live);
- atomic_inc(&current->signal->sigcnt);
+ refcount_inc(&current->signal->sigcnt);
task_join_group_stop(p);
list_add_tail_rcu(&p->thread_group,
&p->group_leader->thread_group);
@@ -2177,6 +2194,11 @@ struct task_struct *fork_idle(int cpu)
return task;
}
+struct mm_struct *copy_init_mm(void)
+{
+ return dup_mm(NULL, &init_mm);
+}
+
/*
* Ok, this is the main fork-routine.
*
@@ -2429,7 +2451,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
return -EINVAL;
}
if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) {
- if (atomic_read(&current->sighand->count) > 1)
+ if (refcount_read(&current->sighand->count) > 1)
return -EINVAL;
}
if (unshare_flags & CLONE_VM) {
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2025-05-02 17:13:19 +0200