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From: Christoph Lameter <cl@linux.com>
To: Sasha Levin <levinsasha928@gmail.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>,
	kaber@trash.net, davem@davemloft.net,
	Dave Jones <davej@redhat.com>,
	netfilter-devel@vger.kernel.org,
	"linux-kernel@vger.kernel.org List"
	<linux-kernel@vger.kernel.org>,
	netdev@vger.kernel.org
Subject: Re: netfilter: Hung task
Date: Mon, 19 Mar 2012 15:03:14 -0500 (CDT)	[thread overview]
Message-ID: <alpine.DEB.2.00.1203191501140.23632@router.home> (raw)
In-Reply-To: <CA+1xoqeinbEVMUGu=zx8nDbdDFx30RiTS=qiSgFKZnSYYPDZ+Q@mail.gmail.com>

On Mon, 19 Mar 2012, Sasha Levin wrote:

> lockdep listed all the held locks there.

None of the locks listed are slub locks.

> I've mentioned that it looks very similar to
> https://lkml.org/lkml/2012/1/14/45 where the userspace helper tried to
> read from the sysfs files, but got into a deadlock since the kernel
> side held them before it called the usermode helper.

Ah yes. In that case slub held a semaphore. Code was changed since then to
no longer hold a semaphore when calling into sysfs.

The uevent handler can execute arbitrary user space code. Do you have to
hold locks while calling kmem_cache_destroy?



      reply	other threads:[~2012-03-19 20:03 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-18 10:55 netfilter: Hung task Sasha Levin
2012-03-18 14:19 ` Pablo Neira Ayuso
2012-03-18 20:52   ` Sasha Levin
2012-03-19  0:28     ` Pablo Neira Ayuso
2012-03-19 13:56       ` Christoph Lameter
2012-03-19 16:13         ` Sasha Levin
2012-03-19 16:31           ` Christoph Lameter
2012-03-19 16:45             ` Sasha Levin
2012-03-19 20:03               ` Christoph Lameter [this message]

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