dm cache: fix missing return in invalidate_committed's error path

In passthrough mode, dm-cache defers write submission until after
metadata commit completes via the invalidate_committed() continuation.
On commit error, invalidate_committed() calls invalidate_complete() to
end the bio and free the migration struct, after which it should return
immediately.

The patch 4ca8b8bd952d ("dm cache: fix write hang in passthrough mode")
omitted this early return, causing execution to fall through into the
success path on error. This results in use-after-free on the migration
struct in the subsequent calls.

Fix by adding the missing return after the invalidate_complete() call.

Fixes: 4ca8b8bd952d ("dm cache: fix write hang in passthrough mode")
Reported-by: Dan Carpenter <error27@gmail.com>
Closes: https://lore.kernel.org/dm-devel/adjMq6T5RRjv_uxM@stanley.mountain/
Signed-off-by: Ming-Hung Tsai <mtsai@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index f8200c15480525961d2be72b6171cee6cdbd2779..097315a9bf0f1334a8540b159a941107119f7101 100644 (file)
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -1521,8 +1521,10 @@ static void invalidate_committed(struct work_struct *ws)
        struct bio *bio = mg->overwrite_bio;
        struct per_bio_data *pb = get_per_bio_data(bio);
 
-       if (mg->k.input)
+       if (mg->k.input) {
                invalidate_complete(mg, false);
+               return;
+       }
 
        init_continuation(&mg->k, invalidate_completed);
        remap_to_origin_clear_discard(cache, bio, mg->invalidate_oblock);