From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Date: Mon, 12 Dec 2005 08:37:07 +0000 (-0800)
Subject: [PATCH] Fix RCU race in access of nohz_cpu_mask
X-Git-Tag: v2.6.15-rc6~136
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c3f5902325d3053986e7359f706581d8f032e72f;p=pandora-kernel.git

[PATCH] Fix RCU race in access of nohz_cpu_mask

Accessing nohz_cpu_mask before incrementing rcp->cur is racy.  It can cause
tickless idle CPUs to be included in rsp->cpumask, which will extend
graceperiods unnecessarily.

Fix this race.  It has been tested using extensions to RCU torture module
that forces various CPUs to become idle.

Signed-off-by: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

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