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authorBianca Lutz <sowilo@cs.tu-berlin.de>2011-07-13 18:13:36 (GMT)
committerIngo Molnar <mingo@elte.hu>2011-07-21 16:01:51 (GMT)
commit99bc52429f11d1f4f81495ac8237085aaeb6bccf (patch)
treeaf5b2f44ceb1382b836dc9171fe296b3d35dd48d /kernel/sched.c
parent045176d22f08bc0b650a028df0f62fc3c2747699 (diff)
downloadlinux-99bc52429f11d1f4f81495ac8237085aaeb6bccf.tar.xz
sched: Do not attempt to destroy uninitialized rt_bandwidth
If a task group is to be created and alloc_fair_sched_group() fails, then the rt_bandwidth of the corresponding task group is not yet initialized. The caller, sched_create_group(), starts a clean up procedure which calls free_rt_sched_group() which unconditionally destroys the not yet initialized rt_bandwidth. This crashes or hangs the system in lock_hrtimer_base(): UP systems dereference a NULL pointer, while SMP systems loop endlessly on a condition that cannot become true. This patch simply avoids the destruction of rt_bandwidth when the initialization code path was not reached. (This was discovered by accident with a custom kernel modification.) Signed-off-by: Bianca Lutz <sowilo@cs.tu-berlin.de> Signed-off-by: Jan Schoenherr <schnhrr@cs.tu-berlin.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1310580816-10861-7-git-send-email-schnhrr@cs.tu-berlin.de Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 3b3826e..f107204 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8383,7 +8383,8 @@ static void free_rt_sched_group(struct task_group *tg)
{
int i;
- destroy_rt_bandwidth(&tg->rt_bandwidth);
+ if (tg->rt_se)
+ destroy_rt_bandwidth(&tg->rt_bandwidth);
for_each_possible_cpu(i) {
if (tg->rt_rq)