3.11.10.15 -stable review patch. If anyone has any objections, please let me know.
------------------
From: David Vrabel <david.vrabel@xxxxxxxxxx>
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
deadlock.
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
[ luis: backported to 3.11: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
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 624e8dc24532..0bc8086064ca 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_irq_resume();
- xen_console_resume();
xen_timer_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) {
--
1.9.1
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