[PATCH stable-28 2/3] PCI hotplug: fix lock imbalance in pciehp

[Jiri Slaby]

From: Jiri Slaby <jirislaby@xxxxxxxxx>

set_lock_status omits mutex_unlock in fail path. Add the omitted
unlock.

As a result a lockup caused by this can be triggered from userspace
by writing 1 to /sys/bus/pci/slots/.../lock often enough.

Commit c2fdd36b550659f5ac2240d1f5a83ffa1a092289.

Signed-off-by: Jiri Slaby <jirislaby@xxxxxxxxx>
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>
Signed-off-by: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
---
 drivers/pci/hotplug/pciehp_core.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 39cf248..b2ecff4 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -126,8 +126,10 @@ static int set_lock_status(struct hotplug_slot *hotplug_slot, u8 status)
 	mutex_lock(&slot->ctrl->crit_sect);
 
 	/* has it been >1 sec since our last toggle? */
-	if ((get_seconds() - slot->last_emi_toggle) < 1)
+	if ((get_seconds() - slot->last_emi_toggle) < 1) {
+		mutex_unlock(&slot->ctrl->crit_sect);
 		return -EINVAL;
+	}
 
 	/* see what our current state is */
 	retval = get_lock_status(hotplug_slot, &value);
-- 
1.6.1

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