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tracing: Add BUG_ON when stack end location is over written

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It is difficult to detect a stack overrun when it
actually occurs.

We have observed that this type of corruption is often
silent and can go unnoticed. Once the corrupted region
is examined, the outcome is undefined and often
results in sporadic system crashes.

When the stack tracing feature is enabled, let's check
for this condition and take appropriate action.

Note: init_task doesn't get its stack end location
set to STACK_END_MAGIC.

Link: http://lkml.kernel.org/r/1395669837-30209-1-git-send-email-atomlin@redhat.com

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Aaron Tomlin 2014-03-24 14:03:57 +00:00 committed by Steven Rostedt
parent 0dea6d5263
commit 3862807880
1 changed files with 3 additions and 0 deletions
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3
kernel/trace/trace_stack.c
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@ -13,6 +13,7 @@
#include <linux/sysctl.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/magic.h>
#include <asm/setup.h>
@ -144,6 +145,8 @@ check_stack(unsigned long ip, unsigned long *stack)
i++;
}
BUG_ON(current != &init_task &&
*(end_of_stack(current)) != STACK_END_MAGIC);
out:
arch_spin_unlock(&max_stack_lock);
local_irq_restore(flags);