From: Tejun Heo <tj@kernel.org>
To: Richard Weinberger <richard@nod.at>
Cc: linux-kernel@vger.kernel.org, Jeff Dike <jdike@addtoit.com>,
Richard Weinberger <richard@nod.at>,
user-mode-linux-devel@lists.sourceforge.net
Subject: Re: [PATCH] print_worker_info: Handle pointer with more care
Date: Fri, 16 Aug 2013 12:28:44 -0400 [thread overview]
Message-ID: <20130816162844.GJ2505@htj.dyndns.org> (raw)
In-Reply-To: <520E500B.5000408@nod.at>
On Fri, Aug 16, 2013 at 06:15:07PM +0200, Richard Weinberger wrote:
> On UML I hit the case that pwq is NULL.
> Then we oops at &pwq->wq...
Hmmm? I'm confused. &pwq->wq is pwq's pointer + wq's offset in pwq.
It doesn't involve dereferencing pwq->wq. Maybe uml isn't
implementing probe_kernel_thread()? Now that I think about it, I'm
not sure how it could.
cc'ing uml people. Hey, guys, workqueue uses proble_kernel_read() to
print out workqueue related information during oops because those
events are completely asynchronous and workqueue states may not be
consistently accessible. It seems like uml doesn't implement
probe_kernel_read() and tries direct derference of incorrect pointers
leading to its own oops. Maybe uml should check whether the memory is
mapped from probe_kernel_read()?
Thanks.
--
tejun
next parent reply other threads:[~2013-08-16 16:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1376668606-32354-1-git-send-email-richard@nod.at>
[not found] ` <20130816161229.GI2505@htj.dyndns.org>
[not found] ` <520E500B.5000408@nod.at>
2013-08-16 16:28 ` Tejun Heo [this message]
2013-08-16 16:38 ` [PATCH] print_worker_info: Handle pointer with more care Richard Weinberger
2013-08-16 16:45 ` Tejun Heo
2013-08-16 16:53 ` Richard Weinberger
2013-08-16 17:20 ` Richard Weinberger
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