On Thu, 9 Apr 2009, Carsten Emde wrote:
> Jan,
>
> > Here are some patches that are necessary to get KVM running with the -rt4
> > patchset.
> Thanks a lot.
>
> Unfortunaately, there is still a last one at kernel/smp.c:288
> /* Can deadlock when called with interrupts disabled */
> WARN_ON_ONCE(irqs_disabled() && !oops_in_progress);
>
> Do we get another fix?
I think I have seen that before. Just remembered that I fixed that
with Avi last year. Patch got dropped in the 26->29 move.
Thanks,
tglx
----
From: Thomas Gleixner <[email protected]>
Date: Mon, 14 Jan 2008 14:02:44 +0200
Subject: CFS: enable irqs in fire_sched_in_preempt_notifier
KVM expects the notifier call with irqs enabled. It's necessary due
to a possible IPI call. Make the preempt-rt version behave the same
way as mainline.
Signed-off-by: Thomas Gleixner <[email protected]>
---
kernel/sched.c | 9 +++++++++
1 file changed, 9 insertions(+)
Index: linux-2.6.24.7-rt27/kernel/sched.c
===================================================================
--- linux-2.6.24.7-rt27.orig/kernel/sched.c 2009-02-08 00:01:16.000000000
-0500
+++ linux-2.6.24.7-rt27/kernel/sched.c 2009-02-08 00:01:22.000000000 -0500
@@ -1821,8 +1821,17 @@ static void fire_sched_in_preempt_notifi
struct preempt_notifier *notifier;
struct hlist_node *node;
+ if (hlist_empty(&curr->preempt_notifiers))
+ return;
+
+ /*
+ * The KVM sched in notifier expects to be called with
+ * interrupts enabled.
+ */
+ local_irq_enable();
hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
notifier->ops->sched_in(notifier, raw_smp_processor_id());
+ local_irq_disable();
}
static void
--
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