From: Alexey Khoroshilov <khoroshilov@ispras.ru>
Date: Fri, 21 Dec 2012 21:44:16 +0000 (+0400)
Subject: mei: fix mismatch in mutex unlock-lock in mei_amthif_read()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=e6028db0146cf5a68dbd1508225ea49840997880;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git

mei: fix mismatch in mutex unlock-lock in mei_amthif_read()

Users of mei_amthif_read() expect it leaves dev->device_lock held,
while there is a path where mei_amthif_read() unlocks device_lock
and returns -ERESTARTSYS.

The patch move code locking device_lock back before the return.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Acked-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/misc/mei/amthif.c b/drivers/misc/mei/amthif.c
index 18794aea606..e40ffd9502d 100644
--- a/drivers/misc/mei/amthif.c
+++ b/drivers/misc/mei/amthif.c
@@ -187,13 +187,13 @@ int mei_amthif_read(struct mei_device *dev, struct file *file,
 		wait_ret = wait_event_interruptible(dev->iamthif_cl.wait,
 			(cb = mei_amthif_find_read_list_entry(dev, file)));
 
+		/* Locking again the Mutex */
+		mutex_lock(&dev->device_lock);
+
 		if (wait_ret)
 			return -ERESTARTSYS;
 
 		dev_dbg(&dev->pdev->dev, "woke up from sleep\n");
-
-		/* Locking again the Mutex */
-		mutex_lock(&dev->device_lock);
 	}