From: Thomas Gleixner <tglx@linutronix.de>
Date: Fri, 12 Mar 2010 19:13:23 +0000 (+0100)
Subject: timer: Try to survive timer callback preempt_count leak
X-Git-Tag: v2.6.35-rc1~492^2~11
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=802702e0c2618465b813242d4dfee6a233ba0beb;p=pandora-kernel.git

timer: Try to survive timer callback preempt_count leak

If a timer callback leaks preempt_count we currently assert a
BUG(). That makes it unnecessarily hard to retrieve information about
the problem especially on laptops and headless stations.

There is a decent chance to survive the preempt_count leak by
restoring the preempt_count to the value before the callback. That
allows in many cases to get valuable information about the root cause
of the problem.

We carried that fixup in preempt-rt for years and were able to decode
such wreckage quite a few times.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linux Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Veen <arjan@infradead.org>
---

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