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| author | David Vrabel <david.vrabel@citrix.com> | 2014-07-02 17:25:23 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-28 08:08:21 -0700 |
| commit | 2104d6a76f422b6cf3b4e795955049a1f45e87be (patch) | |
| tree | dd365d792017325ef47af4b70542df0ef68069bb | |
| parent | 2b37ed20d030836d3d341d71b1f735bd740e6047 (diff) | |
| download | lwn-2104d6a76f422b6cf3b4e795955049a1f45e87be.tar.gz lwn-2104d6a76f422b6cf3b4e795955049a1f45e87be.zip | |
xen/manage: fix potential deadlock when resuming the console
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@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/xen/manage.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c index 32f9236c959f..8684e0e4d41b 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -109,7 +109,6 @@ static int xen_suspend(void *data) if (!si->cancelled) { xen_irq_resume(); - xen_console_resume(); xen_timer_resume(); } @@ -166,6 +165,10 @@ 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); |