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.le...@oracle.com>
Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
---
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;
}
--
2.4.9
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
