Re: netfilter: Hung task

From: Christoph Lameter
Date: Mon Mar 19 2012 - 12:31:49 EST


On Mon, 19 Mar 2012, Sasha Levin wrote:

> On Mon, Mar 19, 2012 at 3:56 PM, Christoph Lameter <cl@xxxxxxxxx> wrote:
> > This is sually something causing memory corruption. Please enable
> > debugging to get backtrace that help to debutg this. CONFIG_SLUB_DEBUG_ON
> > will do the trick or passing "slub_debug" on the kernel command line.
>
> The kernel was compiled with SLUB_DEBUG_ON, there's nothing coming out
> of the slub before that hang message, nor after it.

Ok looking at the backtrace: This is kmem_cache_destroy and not the usual
failure following a pointer in alloc / free.

netfilter calls kmem_cache_destroy which calls into sysfs functions and
there the hang occurs.

Did you try to see if lockdep can detect any serialization problems ?

Is kmem_cache_destroy called with any locks held? Interrupts off?

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