From: Keshavamurthy Anil S <anil.s.keshavamurthy@intel.com>
Date: Wed, 11 Jan 2006 20:17:42 +0000 (-0800)
Subject: [PATCH] kprobes: fix race in recovery of reentrant probe
X-Git-Tag: v2.6.16-rc1~398
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eb3a72921c8276bf2cd028a458bb83435f16c91c;p=pandora-kernel.git

[PATCH] kprobes: fix race in recovery of reentrant probe

There is a window where a probe gets removed right after the probe is hit
on some different cpu.  In this case probe handlers can't find a matching
probe instance related to break address.  In this case we need to read the
original instruction at break address to see if that is not a break/int3
instruction and recover safely.

Previous code had a bug where we were not checking for the above race in
case of reentrant probes and the below patch fixes this race.

Tested on IA64, Powerpc, x86_64.

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

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