From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 9 Dec 2009 10:14:58 +0000 (+0000)
Subject: sched: Use rcu in sys_sched_getscheduler/sys_sched_getparam()
X-Git-Tag: v2.6.33-rc2~48^2~23
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5fe85be081edf0ac92d83f9c39e0ab5c1371eb82;p=pandora-kernel.git

sched: Use rcu in sys_sched_getscheduler/sys_sched_getparam()

read_lock(&tasklist_lock) does not protect
sys_sched_getscheduler and sys_sched_getparam() against a
concurrent update of the policy or scheduler parameters as
do_sched_setscheduler() does not take the tasklist_lock. The
accessed integers can be retrieved w/o locking and are snapshots
anyway.

Using rcu_read_lock() to protect find_task_by_vpid() and prevent
the task struct from going away is not changing the above
situation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20091209100706.753790977@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

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