]> git.karo-electronics.de Git - karo-tx-linux.git/commitdiff
xen: Do not suspend IPI IRQs.
authorIan Campbell <ian.campbell@citrix.com>
Thu, 29 Jul 2010 10:16:35 +0000 (11:16 +0100)
committerGreg Kroah-Hartman <gregkh@suse.de>
Fri, 13 Aug 2010 20:27:34 +0000 (13:27 -0700)
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 <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: xen-devel@lists.xensource.com
LKML-Reference: <1280398595-29708-4-git-send-email-ian.campbell@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/xen/events.c

index db8f506817f0ad30f2b54bde0ff778a7405ba59b..28f133ae76add51719aadbfc1b1f76f3da82bf27 100644 (file)
@@ -536,6 +536,7 @@ 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);