diff options
| author | NeilBrown <neilb@suse.de> | 2010-12-09 17:02:14 +1100 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2010-12-09 17:02:14 +1100 |
| commit | 589a594be1fb8815b3f18e517be696c48664f728 (patch) | |
| tree | 9de6f6b4f9244802ccf77312f7fba8612dd13a75 | |
| parent | 1a855a0606653d2d82506281e2c686bacb4b2f45 (diff) | |
md: protect against NULL reference when waiting to start a raid10.
When we fail to start a raid10 for some reason, we call
md_unregister_thread to kill the thread that was created.
Unfortunately md_thread() will then make one call into the handler
(raid10d) even though md_wakeup_thread has not been called. This is
not safe and as md_unregister_thread is called after mddev->private
has been set to NULL, it will definitely cause a NULL dereference.
So fix this at both ends:
- md_thread should only call the handler if THREAD_WAKEUP has been
set.
- raid10 should call md_unregister_thread before setting things
to NULL just like all the other raid modules do.
This is applicable to 2.6.35 and later.
Cc: stable@kernel.org
Reported-by: "Citizen" <citizen_lee@thecus.com>
Signed-off-by: NeilBrown <neilb@suse.de>
| -rw-r--r-- | drivers/md/md.c | 5 | ||||
| -rw-r--r-- | drivers/md/raid10.c | 2 |
2 files changed, 3 insertions, 4 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index b757da17518..e71c5fa527f 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -6044,9 +6044,8 @@ static int md_thread(void * arg) || kthread_should_stop(), thread->timeout); - clear_bit(THREAD_WAKEUP, &thread->flags); - - thread->run(thread->mddev); + if (test_and_clear_bit(THREAD_WAKEUP, &thread->flags)) + thread->run(thread->mddev); } return 0; diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index c67aa54694a..0641674827f 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -2397,13 +2397,13 @@ static int run(mddev_t *mddev) return 0; out_free_conf: + md_unregister_thread(mddev->thread); if (conf->r10bio_pool) mempool_destroy(conf->r10bio_pool); safe_put_page(conf->tmppage); kfree(conf->mirrors); kfree(conf); mddev->private = NULL; - md_unregister_thread(mddev->thread); out: return -EIO; } |