From: Stanislaw Gruszka <sgruszka@redhat.com>
Date: Thu, 11 Mar 2010 22:04:42 +0000 (-0800)
Subject: cpu-timers: Avoid iterating over all threads in fastpath_timer_check()
X-Git-Tag: v2.6.35-rc1~492^2~15
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c28739375bf0d6e239b4fa939ec8372aa2c707d2;p=pandora-kernel.git

cpu-timers: Avoid iterating over all threads in fastpath_timer_check()

Spread p->sighand->siglock locking scope to make sure that
fastpath_timer_check() never iterates over all threads. Without
locking there is small possibility that signal->cputimer will stop
running while we write values to signal->cputime_expires.

Calling thread_group_cputime() from fastpath_timer_check() is not only
bad because it is slow, also it is racy with __exit_signal() which can
lead to invalid signal->{s,u}time values.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---

Reading git-diff-tree failed