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Date:	Fri,  8 Aug 2014 13:38:56 -0700
From:	Kamal Mostafa <>
Cc:	David Vrabel <>,
	Kamal Mostafa <>
Subject: [PATCH 3.13 113/259] xen/manage: fix potential deadlock when resuming the console -stable review patch.  If anyone has any objections, please let me know.


From: David Vrabel <>

commit 1b6478231c6f5f844185acb32045cf195028cfce upstream.

Calling xen_console_resume() in xen_suspend() causes a warning because
it locks irq_mapping_update_lock (a mutex) and this may sleep.  If a
userspace process is using the evtchn device then this mutex may be
locked at the point of the stop_machine() call and
xen_console_resume() would then deadlock.

Resuming the console after stop_machine() returns avoids this

Signed-off-by: David Vrabel <>
Reviewed-by: Boris Ostrovsky <>
Signed-off-by: Kamal Mostafa <>
 drivers/xen/manage.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index 624e8dc..0bc8086 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -95,7 +95,6 @@ static int xen_suspend(void *data)
 	if (!si->cancelled) {
-		xen_console_resume();
@@ -152,6 +151,10 @@ static void do_suspend(void)
 	err = stop_machine(xen_suspend, &si, cpumask_of(0));
+	/* Resume console as early as possible. */
+	if (!si.cancelled)
+		xen_console_resume();
 	dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
 	if (err) {

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