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authorAndrey Ryabinin <aryabinin@virtuozzo.com>2015-10-19 11:37:18 +0300
committerIngo Molnar <mingo@kernel.org>2015-10-20 11:04:19 +0200
commitf7d27c35ddff7c100d7a98db499ac0040149ac05 (patch)
tree0325b7fa7aa4f92950b003944575f5157c3e844b
parentd976441f44bc5d48635d081d277aa76556ffbf8b (diff)
downloadlinux-f7d27c35ddff7c100d7a98db499ac0040149ac05.tar.bz2
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>
-rw-r--r--arch/x86/kernel/process.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 39e585a554b7..e28db181e4fc 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;
}