Messages in this thread Patch in this message | | | Date | Tue, 20 Oct 2015 02:37:37 -0700 | From | tip-bot for Andrey Ryabinin <> | Subject | [tip:x86/urgent] x86/mm, kasan: Silence KASAN warnings in get_wchan() |
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Commit-ID: f7d27c35ddff7c100d7a98db499ac0040149ac05 Gitweb: http://git.kernel.org/tip/f7d27c35ddff7c100d7a98db499ac0040149ac05 Author: Andrey Ryabinin <aryabinin@virtuozzo.com> AuthorDate: Mon, 19 Oct 2015 11:37:18 +0300 Committer: Ingo Molnar <mingo@kernel.org> 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@oracle.com> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wolfram Gloger <wmglo@dent.med.uni-muenchen.de> Cc: kasan-dev <kasan-dev@googlegroups.com> Link: http://lkml.kernel.org/r/1445243838-17763-3-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- 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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