Re: [bug, netconsole, SLUB] BUG skbuff_head_cache: Poison overwritten

Vegard Nossum
2008-07-21T20:23:46Z

On Mon, Jul 21, 2008 at 6:19 PM, Christoph Lameter
<cl@linux-foundation.org> wrote:
>> (There was recently an odd case of kzalloc() succeeding even though it
>> was called before the slab caches were initialized -- and it only
>> generated a warning about irqs-on happening too early. I just mean to
>> say that it _can_ happen. On another machine, it crashed
>> spectacularly. I guess you're not enabling the netconsole before slab
>> allocator is up?)
>
> Kzalloc for objects > 4k will succeed even during early boot since we will
> directly call into the page allocator.

It wasn't just that; it got into __slab_alloc() and out again. See the
backtrace at http://lkml.org/lkml/2008/7/19/23

It's scary, I know. It's a good thing we have irqtrace :-)

Vegard

--
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
-- E. W. Dijkstra, EWD1036