diff options
| author | NeilBrown <neilb@suse.de> | 2008-02-06 01:39:56 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-06 10:41:19 -0800 |
| commit | 177a99b23ef9878c0cedcc7273108eba8a6e9472 (patch) | |
| tree | 616dd718e94a1e5e8ca536114d5fb91fa780bbc8 | |
| parent | a17184a911195c274104df98a79bec10f57e735d (diff) | |
md: fix use-after-free bug when dropping an rdev from an md array
Due to possible deadlock issues we need to use a schedule work to kobject_del
an 'rdev' object from a different thread.
A recent change means that kobject_add no longer gets a refernce, and
kobject_del doesn't put a reference. Consequently, we need to explicitly hold
a reference to ensure that the last reference isn't dropped before the
scheduled work get a chance to call kobject_del.
Also, rename delayed_delete to md_delayed_delete to that it is more obvious in
a stack trace which code is to blame.
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/md/md.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 08e0f8d672c..6cdd1b4faca 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -1419,10 +1419,11 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev) return err; } -static void delayed_delete(struct work_struct *ws) +static void md_delayed_delete(struct work_struct *ws) { mdk_rdev_t *rdev = container_of(ws, mdk_rdev_t, del_work); kobject_del(&rdev->kobj); + kobject_put(&rdev->kobj); } static void unbind_rdev_from_array(mdk_rdev_t * rdev) @@ -1441,7 +1442,8 @@ static void unbind_rdev_from_array(mdk_rdev_t * rdev) /* We need to delay this, otherwise we can deadlock when * writing to 'remove' to "dev/state" */ - INIT_WORK(&rdev->del_work, delayed_delete); + INIT_WORK(&rdev->del_work, md_delayed_delete); + kobject_get(&rdev->kobj); schedule_work(&rdev->del_work); } @@ -3686,7 +3688,7 @@ static int do_md_stop(mddev_t * mddev, int mode) sysfs_remove_link(&mddev->kobj, nm); } - /* make sure all delayed_delete calls have finished */ + /* make sure all md_delayed_delete calls have finished */ flush_scheduled_work(); export_array(mddev); |