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| author | NeilBrown <neilb@suse.de> | 2013-07-24 05:37:42 (GMT) |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2013-07-25 06:46:53 (GMT) |
| commit | 0eb25bb027a100f5a9df8991f2f628e7d851bc1e (patch) | |
| tree | 3e00b7a00db585cf166899506d5fda04ab06a17e | |
| parent | 30bc9b53878a9921b02e3b5bc4283ac1c6de102a (diff) | |
| download | linux-0eb25bb027a100f5a9df8991f2f628e7d851bc1e.tar.xz | |
md/raid10: remove use-after-free bug.
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.
Cc: stable@vger.kernel.org (3.3+)
Signed-off-by: NeilBrown <neilb@suse.de>
| -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 957a719..df7b0a0 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -2290,12 +2290,18 @@ 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, bio_sectors(wbio)); 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, bio_sectors(wbio2)); |