block: bfq: swap puts in bfqg_and_blkg_put

commit d5274b3 upstream. Fix trivial use-after-free. This could be last reference to bfqg. Fixes: 8f9bebc ("block, bfq: access and cache blkg data only when safe") Acked-by: Paolo Valente <[email protected]> Signed-off-by: Konstantin Khlebnikov <[email protected]> Signed-off-by: Jens Axboe <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
maraz · Sep 19, 2018 · 381992b · 381992b
1 parent 23ecbba
commit 381992b
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
@@ -224,9 +224,9 @@ static void bfqg_and_blkg_get(struct bfq_group *bfqg)
 
 void bfqg_and_blkg_put(struct bfq_group *bfqg)
 {
-	bfqg_put(bfqg);
-
 	blkg_put(bfqg_to_blkg(bfqg));
+
+	bfqg_put(bfqg);
 }
 
 void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq,