Commit 047106ad authored Nov 16, 2009 by Peter Zijlstra Committed by Ingo Molnar Nov 16, 2009

sched: Sched_rt_periodic_timer vs cpu hotplug



Heiko reported a case where a timer interrupt managed to
reference a root_domain structure that was already freed by a
concurrent hot-un-plug operation.

Solve this like the regular sched_domain stuff is also
synchronized, by adding a synchronize_sched() stmt to the free
path, this ensures that a root_domain stays present for any
atomic section that could have observed it.

Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Gregory Haskins <ghaskins@novell.com>
Cc: Siddha Suresh B <suresh.b.siddha@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
LKML-Reference: <1258363873.26714.83.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 498657a4

kernel/sched.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -7912,6 +7912,8 @@ sd_parent_degenerate(struct sched_domain sd, struct sched_domain parent)

		static void free_rootdomain(struct root_domain *rd)
		{
		synchronize_sched();

		cpupri_cleanup(&rd->cpupri);

		free_cpumask_var(rd->rto_mask);

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