[patch 40/43] PCI hotplug: fix lock imbalance in pciehp

Greg KH
2009-01-31T03:13:45Z

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2.6.28-stable review patch. If anyone has any objections, please let us know.

------------------

From: Jiri Slaby <jirislaby@gmail.com>

commit c2fdd36b550659f5ac2240d1f5a83ffa1a092289 upstream.

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.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/pci/hotplug/pciehp_core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -126,8 +126,10 @@ static int set_lock_status(struct hotplu
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);