From 7d9deb060ffb6c6b38414210f1f2589c524ad1d6 Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Thu, 29 Jul 2010 11:16:35 +0100 Subject: [PATCH] xen: Do not suspend IPI IRQs. commit 4877c737283813bdb4bebfa3168c1585f6e3a8ca upstream. In general the semantics of IPIs are that they are are expected to continue functioning after dpm_suspend_noirq(). Specifically I have seen a deadlock between the callfunc IPI and the stop machine used by xen's do_suspend() routine. If one CPU has already called dpm_suspend_noirq() then there is a window where it can be sent a callfunc IPI before all the other CPUs have entered stop_cpu(). If this happens then the first CPU ends up spinning in stop_cpu() waiting for the other to rendezvous in state STOPMACHINE_PREPARE while the other is spinning in csd_lock_wait(). Signed-off-by: Ian Campbell Cc: Jeremy Fitzhardinge Cc: xen-devel@lists.xensource.com LKML-Reference: <1280398595-29708-4-git-send-email-ian.campbell@citrix.com> Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- drivers/xen/events.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/xen/events.c b/drivers/xen/events.c index ce602dd09bc1..30e04672ba65 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -535,6 +535,7 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi, if (irq < 0) return irq; + irqflags |= IRQF_NO_SUSPEND; retval = request_irq(irq, handler, irqflags, devname, dev_id); if (retval != 0) { unbind_from_irq(irq); -- 2.39.5