diff options
| author | David Vrabel <david.vrabel@citrix.com> | 2014-07-02 17:25:23 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-08-06 18:07:34 +0100 |
| commit | 8a9c266c7bbac51a32d70ca0bc9e70a54233b89e (patch) | |
| tree | c0eb2385c63fe7ac7e4eabda28e53c7d4cc92cbd /drivers | |
| parent | 74d31de64a0bc7a37a0020e9ddb10af1047ddbbf (diff) | |
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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers')
| -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 ce4fa0831860..c8af7e5e3b18 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -93,7 +93,6 @@ static int xen_suspend(void *data) if (!si->cancelled) { xen_irq_resume(); - xen_console_resume(); xen_timer_resume(); } @@ -149,6 +148,10 @@ 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_noirq(si.cancelled ? PMSG_THAW : PMSG_RESTORE); if (err) { |