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authorDavid Vrabel <david.vrabel@citrix.com>2014-07-02 17:25:23 +0100
committerDavid Vrabel <david.vrabel@citrix.com>2014-07-03 11:02:28 +0100
commit1b6478231c6f5f844185acb32045cf195028cfce (patch)
tree857d9e129051b69c8207c9785a74849dc03e0158
parent13cd36a37a06ae0318d23b7e60adf0dac3547238 (diff)
downloadop-kernel-dev-1b6478231c6f5f844185acb32045cf195028cfce.zip
op-kernel-dev-1b6478231c6f5f844185acb32045cf195028cfce.tar.gz
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 <david.vrabel@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: <stable@vger.kernel.org>
-rw-r--r--drivers/xen/manage.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index c3667b2..5f1e1f3 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);
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