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| 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 /drivers/md/md.c | |
| parent | 1a855a0606653d2d82506281e2c686bacb4b2f45 (diff) | |
| download | linux-589a594be1fb8815b3f18e517be696c48664f728.tar.gz linux-589a594be1fb8815b3f18e517be696c48664f728.tar.bz2 linux-589a594be1fb8815b3f18e517be696c48664f728.zip | |
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>
Diffstat (limited to 'drivers/md/md.c')
| -rw-r--r-- | drivers/md/md.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index b757da175180..e71c5fa527f5 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; |