[patch 63/73] Fix unbalanced helper_lock in kernel/kmod.c

[Greg KH]

2.6.23-stable review patch.  If anyone has any objections, please let us know.
------------------
From: Nigel Cunningham <nigel@xxxxxxxxxxxxxxxxxx>

patch 784680336b616dcc4c17cbd25add3b49c555cdeb in mainline.

call_usermodehelper_exec() has an exit path that can leave the
helper_lock() call at the top of the routine unbalanced.  The attached
patch fixes this issue.

Signed-off-by: Nigel Cunningham <nigel@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 kernel/kmod.c |   13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -451,13 +451,11 @@ int call_usermodehelper_exec(struct subp
 			     enum umh_wait wait)
 {
 	DECLARE_COMPLETION_ONSTACK(done);
-	int retval;
+	int retval = 0;
 
 	helper_lock();
-	if (sub_info->path[0] == '\0') {
-		retval = 0;
+	if (sub_info->path[0] == '\0')
 		goto out;
-	}
 
 	if (!khelper_wq || usermodehelper_disabled) {
 		retval = -EBUSY;
@@ -468,13 +466,14 @@ int call_usermodehelper_exec(struct subp
 	sub_info->wait = wait;
 
 	queue_work(khelper_wq, &sub_info->work);
-	if (wait == UMH_NO_WAIT) /* task has freed sub_info */
-		return 0;
+	if (wait == UMH_NO_WAIT)	/* task has freed sub_info */
+		goto unlock;
 	wait_for_completion(&done);
 	retval = sub_info->retval;
 
-  out:
+out:
 	call_usermodehelper_freeinfo(sub_info);
+unlock:
 	helper_unlock();
 	return retval;
 }

-- 
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