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authorNeilBrown <neilb@suse.de>2011-09-10 17:21:23 +1000
committerNeilBrown <neilb@suse.de>2011-09-10 17:21:23 +1000
commit079fa166a2874985ae58b2e21e26e1cbc91127d4 (patch)
tree39f67f9078465bd67c29216b35370a78907e4f3b
parent19d5f834d6aff7efb1c9353523865c5bce869470 (diff)
downloadlinux-stericsson-079fa166a2874985ae58b2e21e26e1cbc91127d4.tar.gz
md/raid1,10: Remove use-after-free bug in make_request.
A single request to RAID1 or RAID10 might result in multiple requests if there are known bad blocks that need to be avoided. To detect if we need to submit another write request we test: if (sectors_handled < (bio->bi_size >> 9)) { However this is after we call **_write_done() so the 'bio' no longer belongs to us - the writes could have completed and the bio freed. So move the **_write_done call until after the test against bio->bi_size. This addresses https://bugzilla.kernel.org/show_bug.cgi?id=41862 Reported-by: Bruno Wolff III <bruno@wolff.to> Tested-by: Bruno Wolff III <bruno@wolff.to> Signed-off-by: NeilBrown <neilb@suse.de>
-rw-r--r--drivers/md/raid1.c14
-rw-r--r--drivers/md/raid10.c13
2 files changed, 17 insertions, 10 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 32323f0afd89..f4622dd8fc59 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1099,12 +1099,11 @@ read_again:
bio_list_add(&conf->pending_bio_list, mbio);
spin_unlock_irqrestore(&conf->device_lock, flags);
}
- r1_bio_write_done(r1_bio);
-
- /* In case raid1d snuck in to freeze_array */
- wake_up(&conf->wait_barrier);
-
+ /* Mustn't call r1_bio_write_done before this next test,
+ * as it could result in the bio being freed.
+ */
if (sectors_handled < (bio->bi_size >> 9)) {
+ r1_bio_write_done(r1_bio);
/* We need another r1_bio. It has already been counted
* in bio->bi_phys_segments
*/
@@ -1117,6 +1116,11 @@ read_again:
goto retry_write;
}
+ r1_bio_write_done(r1_bio);
+
+ /* In case raid1d snuck in to freeze_array */
+ wake_up(&conf->wait_barrier);
+
if (do_sync || !bitmap || !plugged)
md_wakeup_thread(mddev->thread);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index f6873fc8e5ee..d7a8468ddeab 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1132,13 +1132,12 @@ retry_write:
spin_unlock_irqrestore(&conf->device_lock, flags);
}
- /* Remove the bias on 'remaining' */
- one_write_done(r10_bio);
-
- /* In case raid10d snuck in to freeze_array */
- wake_up(&conf->wait_barrier);
+ /* Don't remove the bias on 'remaining' (one_write_done) until
+ * after checking if we need to go around again.
+ */
if (sectors_handled < (bio->bi_size >> 9)) {
+ one_write_done(r10_bio);
/* We need another r10_bio. It has already been counted
* in bio->bi_phys_segments.
*/
@@ -1152,6 +1151,10 @@ retry_write:
r10_bio->state = 0;
goto retry_write;
}
+ one_write_done(r10_bio);
+
+ /* In case raid10d snuck in to freeze_array */
+ wake_up(&conf->wait_barrier);
if (do_sync || !mddev->bitmap || !plugged)
md_wakeup_thread(mddev->thread);