Commit 5f7865f3 authored Sep 25, 2012 by Tang Chen Committed by Ingo Molnar Oct 05, 2012

sched: Ensure 'sched_domains_numa_levels' is safe to use in other functions

We should temporarily reset 'sched_domains_numa_levels' to 0 after
it is reset to 'level' in sched_init_numa(). If it fails to allocate
memory for array sched_domains_numa_masks[][], the array will contain
less then 'level' members. This could be dangerous when we use it to
iterate array sched_domains_numa_masks[][] in other functions.

This patch set sched_domains_numa_levels to 0 before initializing
array sched_domains_numa_masks[][], and reset it to 'level' when
sched_domains_numa_masks[][] is fully initialized.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1348578751-16904-2-git-send-email-tangchen@cn.fujitsu.com

Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 2b17c545

kernel/sched/core.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -6122,6 +6122,17 @@ static void sched_init_numa(void)
		* numbers.
		*/

		/*
		* Here, we should temporarily reset sched_domains_numa_levels to 0.
		* If it fails to allocate memory for array sched_domains_numa_masks[][],
		* the array will contain less then 'level' members. This could be
		* dangerous when we use it to iterate array sched_domains_numa_masks[][]
		* in other functions.
		*
		* We reset it to 'level' at the end of this function.
		*/
		sched_domains_numa_levels = 0;

		sched_domains_numa_masks = kzalloc(sizeof(void ) level, GFP_KERNEL);
		if (!sched_domains_numa_masks)
		return;
		@@ -6176,6 +6187,8 @@ static void sched_init_numa(void)
		}

		sched_domain_topology = tl;

		sched_domains_numa_levels = level;
		}
		#else
		static inline void sched_init_numa(void)