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authorRoss Lagerwall <ross.lagerwall@citrix.com>2014-08-18 10:41:36 +0100
committerDavid Vrabel <david.vrabel@citrix.com>2014-09-02 15:36:59 +0100
commit61a734d305e16944b42730ef582a7171dc733321 (patch)
tree9b2881c503893fadb5b219a2b88f72461d2ccd7e /drivers/xen
parent7d951f3ccb0308c95bf76d5eef9886dea35a7013 (diff)
xen/manage: Always freeze/thaw processes when suspend/resuming
Always freeze processes when suspending and thaw processes when resuming to prevent a race noticeable with HVM guests. This prevents a deadlock where the khubd kthread (which is designed to be freezable) acquires a usb device lock and then tries to allocate memory which requires the disk which hasn't been resumed yet. Meanwhile, the xenwatch thread deadlocks waiting for the usb device lock. Freezing processes fixes this because the khubd thread is only thawed after the xenwatch thread finishes resuming all the devices. Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/manage.c7
1 files changed, 0 insertions, 7 deletions
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index 5f1e1f3cd186..f8bb36f9d9ce 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -103,16 +103,11 @@ static void do_suspend(void)
shutting_down = SHUTDOWN_SUSPEND;
-#ifdef CONFIG_PREEMPT
- /* If the kernel is preemptible, we need to freeze all the processes
- to prevent them from being in the middle of a pagetable update
- during suspend. */
err = freeze_processes();
if (err) {
pr_err("%s: freeze failed %d\n", __func__, err);
goto out;
}
-#endif
err = dpm_suspend_start(PMSG_FREEZE);
if (err) {
@@ -157,10 +152,8 @@ out_resume:
dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
out_thaw:
-#ifdef CONFIG_PREEMPT
thaw_processes();
out:
-#endif
shutting_down = SHUTDOWN_INVALID;
}
#endif /* CONFIG_HIBERNATE_CALLBACKS */