drivers/message/i2o/i2o_config.c: fix deadlock in compat_ioctl(I2OGET…

…IOPS) i2o_cfg_compat_ioctl(I2OGETIOPS) locks i2o_cfg_mutex and then calls i2o_cfg_ioctl(I2OGETIOPS) that locks i2o_cfg_mutex as well. A deadlock is guaranteed. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
Baughn · Feb 11, 2014 · a3eb7fb · a3eb7fb
1 parent 3cf8ca1
commit a3eb7fb
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/drivers/message/i2o/i2o_config.c b/drivers/message/i2o/i2o_config.c
@@ -754,19 +754,19 @@ static long i2o_cfg_compat_ioctl(struct file *file, unsigned cmd,
 				 unsigned long arg)
 {
 	int ret;
-	mutex_lock(&i2o_cfg_mutex);
 	switch (cmd) {
 	case I2OGETIOPS:
 		ret = i2o_cfg_ioctl(file, cmd, arg);
 		break;
 	case I2OPASSTHRU32:
+		mutex_lock(&i2o_cfg_mutex);
 		ret = i2o_cfg_passthru32(file, cmd, arg);
+		mutex_unlock(&i2o_cfg_mutex);
 		break;
 	default:
 		ret = -ENOIOCTLCMD;
 		break;
 	}
-	mutex_unlock(&i2o_cfg_mutex);
 	return ret;
 }