diff options
| author | NeilBrown <neilb@suse.de> | 2013-07-24 15:37:42 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-04 16:26:00 +0800 |
| commit | aa2f8abe27dd7058fd7bfe52401121037a285406 (patch) | |
| tree | 241e0890bf19f715834bb5ee6584a4cebab7ef5b | |
| parent | 0761d079bbc23ffd309c586ddd142b3cb5f11e0d (diff) | |
md/raid10: remove use-after-free bug.
commit 0eb25bb027a100f5a9df8991f2f628e7d851bc1e upstream.
We always need to be careful when calling generic_make_request, as it
can start a chain of events which might free something that we are
using.
Here is one place I wasn't careful enough. If the wbio2 is not in
use, then it might get freed at the first generic_make_request call.
So perform all necessary tests first.
This bug was introduced in 3.3-rc3 (24afd80d99) and can cause an
oops, so fix is suitable for any -stable since then.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/md/raid10.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 0cc798582b2..54ba5315342 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -2029,12 +2029,18 @@ static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio) d = r10_bio->devs[1].devnum; wbio = r10_bio->devs[1].bio; wbio2 = r10_bio->devs[1].repl_bio; + /* Need to test wbio2->bi_end_io before we call + * generic_make_request as if the former is NULL, + * the latter is free to free wbio2. + */ + if (wbio2 && !wbio2->bi_end_io) + wbio2 = NULL; if (wbio->bi_end_io) { atomic_inc(&conf->mirrors[d].rdev->nr_pending); md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9); generic_make_request(wbio); } - if (wbio2 && wbio2->bi_end_io) { + if (wbio2) { atomic_inc(&conf->mirrors[d].replacement->nr_pending); md_sync_acct(conf->mirrors[d].replacement->bdev, wbio2->bi_size >> 9); |