Messages in this thread Patch in this message | | | Date | Tue, 22 Apr 2008 11:44:12 -0500 | From | Eric Sandeen <> | Subject | Re: [PATCH] use canary at end of stack to indicate overruns at oops time |
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Ingo Molnar wrote: > * Eric Sandeen <sandeen@redhat.com> wrote:
>> With the code in place, an intentionally-bloated stack oops does: >> >> BUG: unable to handle kernel paging request at ffff8103f84cc680 >> IP: [<ffffffff810253df>] update_curr+0x9a/0xa8 >> PGD 8063 PUD 0 >> Thread overran stack or stack corrupted >> Oops: 0000 [1] SMP >> CPU 0 >> ... > > excellent. I've queued this up, it's definitely an improvement in > debuggability.
Crud, just realized this probably doesn't play well with CONFIG_DEBUG_STACK_USAGE. I think it will need something like:
Index: linux-2.6.25-rc7/kernel/exit.c =================================================================== --- linux-2.6.25-rc7.orig/kernel/exit.c 2008-04-20 22:34:16.000000000 -0500 +++ linux-2.6.25-rc7/kernel/exit.c 2008-04-22 11:38:05.769412824 -0500 @@ -826,6 +826,8 @@ static void check_stack_usage(void) unsigned long *n = end_of_stack(current); unsigned long free;
+ n++; /* skip over canary at end */ + while (*n == 0) n++; free = (unsigned long)n - (unsigned long)end_of_stack(current);
Testing now... want me to resend the whole patch, Ingo, or you want to just fix it up? (I'll follow up with the testing results)
Thanks, -Eric
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