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

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Date:	Wed, 28 Jan 2009 18:53:40 +0100
From:	Jiri Slaby <jslaby@...e.cz>
To:	greg@...ah.com
Cc:	chrisw@...s-sol.org, stable@...nel.org,
	linux-kernel@...r.kernel.org, Jiri Slaby <jirislaby@...il.com>,
	Jesse Barnes <jbarnes@...tuousgeek.org>
Subject: [PATCH stable-28 2/3] PCI hotplug: fix lock imbalance in pciehp

From: Jiri Slaby <jirislaby@...il.com>

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@...il.com>
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@...tuousgeek.org>
---
 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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