From: Todd Poynor <toddpoynor@google.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org
Subject: Crash in schedule path after worker thread dies
Date: Tue, 19 Jul 2011 17:07:38 -0700 [thread overview]
Message-ID: <20110720000738.GA18774@google.com> (raw)
After a worker thread died due to a bug in a work function, a NULL
dereference was seen when schedule calls wq_worker_sleeping calls
kthread_data:
return to_kthread(task)->data;
mm_release has apparently already set the task's vfork_done = NULL,
causing to_kthread to return a bad address (on 3.0-rc7 on ARM).
I haven't tried a fix because I'm not sure if avoiding this case is
enough to properly recover from death of a worker thread, or if this
has already been discussed and rejected in the past. I searched
around a little and found some mentions of problems in worker
functions that were probably followed by the kthread_data crash,
but didn't turn up any specific discussion of this crash. So I
thought I'd start by mentioning this here, and can help fix or test if
needed.
Todd
next reply other threads:[~2011-07-20 0:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-20 0:07 Todd Poynor [this message]
2011-07-20 17:07 ` Crash in schedule path after worker thread dies Tejun Heo
2011-07-20 18:06 ` Todd Poynor
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