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-rw-r--r--kernel/events/uprobes.c43
1 files changed, 28 insertions, 15 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 5cc4e7e42e68..dea7acfbb071 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -33,6 +33,7 @@
#include <linux/ptrace.h> /* user_enable_single_step */
#include <linux/kdebug.h> /* notifier mechanism */
#include "../../mm/internal.h" /* munlock_vma_page */
+#include <linux/percpu-rwsem.h>
#include <linux/uprobes.h>
@@ -71,6 +72,8 @@ static struct mutex uprobes_mutex[UPROBES_HASH_SZ];
static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ])
+static struct percpu_rw_semaphore dup_mmap_sem;
+
/*
* uprobe_events allows us to skip the uprobe_mmap if there are no uprobe
* events active at this time. Probably a fine grained per inode count is
@@ -766,10 +769,13 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
struct map_info *info;
int err = 0;
+ percpu_down_write(&dup_mmap_sem);
info = build_map_info(uprobe->inode->i_mapping,
uprobe->offset, is_register);
- if (IS_ERR(info))
- return PTR_ERR(info);
+ if (IS_ERR(info)) {
+ err = PTR_ERR(info);
+ goto out;
+ }
while (info) {
struct mm_struct *mm = info->mm;
@@ -799,7 +805,8 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
mmput(mm);
info = free_map_info(info);
}
-
+ out:
+ percpu_up_write(&dup_mmap_sem);
return err;
}
@@ -1131,6 +1138,16 @@ void uprobe_clear_state(struct mm_struct *mm)
kfree(area);
}
+void uprobe_start_dup_mmap(void)
+{
+ percpu_down_read(&dup_mmap_sem);
+}
+
+void uprobe_end_dup_mmap(void)
+{
+ percpu_up_read(&dup_mmap_sem);
+}
+
void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm)
{
newmm->uprobes_state.xol_area = NULL;
@@ -1199,6 +1216,11 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot
vaddr = kmap_atomic(area->page);
memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES);
kunmap_atomic(vaddr);
+ /*
+ * We probably need flush_icache_user_range() but it needs vma.
+ * This should work on supported architectures too.
+ */
+ flush_dcache_page(area->page);
return current->utask->xol_vaddr;
}
@@ -1430,16 +1452,6 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
return uprobe;
}
-void __weak arch_uprobe_enable_step(struct arch_uprobe *arch)
-{
- user_enable_single_step(current);
-}
-
-void __weak arch_uprobe_disable_step(struct arch_uprobe *arch)
-{
- user_disable_single_step(current);
-}
-
/*
* Run handler and ask thread to singlestep.
* Ensure all non-fatal signals cannot interrupt thread while it singlesteps.
@@ -1493,7 +1505,6 @@ static void handle_swbp(struct pt_regs *regs)
goto out;
if (!pre_ssout(uprobe, regs, bp_vaddr)) {
- arch_uprobe_enable_step(&uprobe->arch);
utask->active_uprobe = uprobe;
utask->state = UTASK_SSTEP;
return;
@@ -1525,7 +1536,6 @@ static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs)
else
WARN_ON_ONCE(1);
- arch_uprobe_disable_step(&uprobe->arch);
put_uprobe(uprobe);
utask->active_uprobe = NULL;
utask->state = UTASK_RUNNING;
@@ -1604,6 +1614,9 @@ static int __init init_uprobes(void)
mutex_init(&uprobes_mmap_mutex[i]);
}
+ if (percpu_init_rwsem(&dup_mmap_sem))
+ return -ENOMEM;
+
return register_die_notifier(&uprobe_exception_nb);
}
module_init(init_uprobes);