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

Greg KH
2008-02-07T00:27:19Z

[-- Attachment #1: fix-unbalanced-helper_lock-in-kernel-kmod.c.patch --]
[-- Type: text/plain, Size: 1522 bytes --]

2.6.23-stable review patch. If anyone has any objections, please let us know.
------------------
From: Nigel Cunningham <nigel@nigel.suspend2.net>

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@tuxonice.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
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;
}

--