From 1b6478231c6f5f844185acb32045cf195028cfce Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Wed, 2 Jul 2014 17:25:23 +0100 Subject: xen/manage: fix potential deadlock when resuming the console 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 Reviewed-by: Boris Ostrovsky Cc: --- 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 c3667b202f2f..5f1e1f3cd186 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -88,7 +88,6 @@ static int xen_suspend(void *data) if (!si->cancelled) { xen_irq_resume(); - xen_console_resume(); xen_timer_resume(); } @@ -135,6 +134,10 @@ 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(); + raw_notifier_call_chain(&xen_resume_notifier, 0, NULL); dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE); -- cgit v1.2.3