Re: Hung task when calling clone() due to netfilter/slab

From: Christoph Lameter
Date: Fri Jan 20 2012 - 09:50:08 EST


On Thu, 19 Jan 2012, Eric W. Biederman wrote:

> On the flip side removing from sysfs with locks held must be done
> carefully, and as a default I would recommend not to hold locks over
> removing things from sysfs. As removal blocks waiting for all of the
> callers into sysfs those sysfs attributes to complete.
>
> It looks like you are ok on the removal because none of the sysfs
> attributes appear to take the slub_lock, just /proc/slabinfo. But
> it does look like playing with fire.

Ok then I guess my last patch is needed to make sysfs operations safe.

It may be good to audit the kernel for locks being held while calling
sysfs functions. Isnt there a lockdep check that ensures that no locks are
held?


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