Commit-ID: f7d27c35ddff7c100d7a98db499ac0040149ac05
Gitweb: http://git.kernel.org/tip/f7d27c35ddff7c100d7a98db499ac0040149ac05
Author: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
AuthorDate: Mon, 19 Oct 2015 11:37:18 +0300
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 20 Oct 2015 11:04:19 +0200
x86/mm, kasan: Silence KASAN warnings in get_wchan()
get_wchan() is racy by design, it may access volatile stack
of running task, thus it may access redzone in a stack frame
and cause KASAN to warn about this.
Use READ_ONCE_NOCHECK() to silence these warnings.
Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Kostya Serebryany <kcc@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Wolfram Gloger <wmglo@xxxxxxxxxxxxxxxxxxxxxxxx>
Cc: kasan-dev <kasan-dev@xxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1445243838-17763-3-git-send-email-aryabinin@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/process.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 39e585a..e28db18 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -550,14 +550,14 @@ unsigned long get_wchan(struct task_struct *p)
if (sp < bottom || sp > top)
return 0;
- fp = READ_ONCE(*(unsigned long *)sp);
+ fp = READ_ONCE_NOCHECK(*(unsigned long *)sp);
do {
if (fp < bottom || fp > top)
return 0;
- ip = READ_ONCE(*(unsigned long *)(fp + sizeof(unsigned long)));
+ ip = READ_ONCE_NOCHECK(*(unsigned long *)(fp + sizeof(unsigned long)));
if (!in_sched_functions(ip))
return ip;
- fp = READ_ONCE(*(unsigned long *)fp);
+ fp = READ_ONCE_NOCHECK(*(unsigned long *)fp);
} while (count++ < 16 && p->state != TASK_RUNNING);
return 0;
}
--
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