Messages in this thread Patch in this message | | | From | Jan H. Schönherr <> | Subject | [PATCH 6/6] sched: Do not attempt to destroy uninitialized rt_bandwidth | Date | Wed, 13 Jul 2011 20:13:36 +0200 |
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From: Bianca Lutz <sowilo@cs.tu-berlin.de>
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 H. Schönherr <schnhrr@cs.tu-berlin.de> --- kernel/sched.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c index 9a5f4c7..f29077c 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8268,7 +8268,8 @@ 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) -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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