Messages in this thread Patch in this message | | | Date | Thu, 12 Feb 2009 11:50:27 +0100 | From | Ingo Molnar <> | Subject | [patch] sched: cpu hotplug fix |
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The fix below addresses a lockdep warning i triggered with your config.
(You could hit this if you try to use s2ram or hibernation or explicit CPU hotplug ops.)
Ingo
--------------> Subject: sched: cpu hotplug fix From: Ingo Molnar <mingo@elte.hu> Date: Thu Feb 12 11:35:40 CET 2009
rq_attach_root() does a kfree() with the runqueue lock held.
That's not a very wise move, fix it.
Signed-off-by: Ingo Molnar <mingo@elte.hu> --- kernel/sched.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
Index: tip/kernel/sched.c =================================================================== --- tip.orig/kernel/sched.c +++ tip/kernel/sched.c @@ -7619,20 +7619,26 @@ static void free_rootdomain(struct root_ static void rq_attach_root(struct rq *rq, struct root_domain *rd) { + struct root_domain *old_rd = NULL; unsigned long flags; spin_lock_irqsave(&rq->lock, flags); if (rq->rd) { - struct root_domain *old_rd = rq->rd; + old_rd = rq->rd; if (cpumask_test_cpu(rq->cpu, old_rd->online)) set_rq_offline(rq); cpumask_clear_cpu(rq->cpu, old_rd->span); - if (atomic_dec_and_test(&old_rd->refcount)) - free_rootdomain(old_rd); + /* + * If we dont want to free the old_rt yet then + * set old_rd to NULL to skip the freeing later + * in this function: + */ + if (!atomic_dec_and_test(&old_rd->refcount)) + old_rd = NULL; } atomic_inc(&rd->refcount); @@ -7643,6 +7649,9 @@ static void rq_attach_root(struct rq *rq set_rq_online(rq); spin_unlock_irqrestore(&rq->lock, flags); + + if (old_rd) + free_rootdomain(old_rd); } static int __init_refok init_rootdomain(struct root_domain *rd, bool bootmem)
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