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authorNeilBrown <neilb@suse.de>2010-12-09 17:02:14 +1100
committerNeilBrown <neilb@suse.de>2010-12-09 17:02:14 +1100
commit589a594be1fb8815b3f18e517be696c48664f728 (patch)
tree9de6f6b4f9244802ccf77312f7fba8612dd13a75 /drivers/md
parent1a855a0606653d2d82506281e2c686bacb4b2f45 (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>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/md.c5
-rw-r--r--drivers/md/raid10.c2
2 files changed, 3 insertions, 4 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;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index c67aa54694ae..0641674827f0 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;
}