Messages in this thread | | | Date | Fri, 18 Jul 2008 02:16:40 +0200 | From | Ingo Molnar <> | Subject | Re: [bug, netconsole, SLUB] BUG skbuff_head_cache: Poison overwritten |
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* Vegard Nossum <vegard.nossum@gmail.com> wrote:
> On Fri, Jul 18, 2008 at 1:52 AM, Ingo Molnar <mingo@elte.hu> wrote: > > If only we had some kernel technology that could track and validate > > memory accesses, and point out the cases where we access uninitialized > > memory, just like Valgrind? > > > > ... something like kmemcheck? ;-) > > Cool :) > > > So i booted that box with tip/master and kmemcheck enabled. (plus a few > > fixlets to make networking allocations be properly tracked by > > kmemcheck.) > > > > It was a slow bootup and long wait, but it gave a few hits here: > > Hm, if you think it was that slow, I am suspecting you were also using > SLUB debugging.
nope:
# CONFIG_SLUB_DEBUG is not set CONFIG_SLUB=y
> This can actually be negative, since now SLUB will access the objects > (+redzone +padding) and possibly trick kmemcheck into thinking they > were initialized in the first place. > > But what we are really looking for is "read from freed memory" > messages. So I would actually recommend this: Disable kmemcheck's > reporting of uninitialized memory, simply to make it easier to spot > the "freed" messages more easily. > > Maybe something like this (warning: whitespace-munged):
ok, applied this too.
> If this only happens during boot, it would also be a good idea to > simply reboot the machine a lot...
yeah, i've got a script for that. Will try it overnight.
Ingo
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