blk-cgroup: Fix memleak on error path

krisman-at-collabora · gregkh · commit 89c94a3a8ea2 · 2020-11-10T12:39:04.000+01:00
[ Upstream commit 52abfcb ] If new_blkg allocation raced with blk_policy change and blkg_lookup_check fails, new_blkg is leaked. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
@@ -654,6 +654,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 		blkg = blkg_lookup_check(pos, pol, q);
 		if (IS_ERR(blkg)) {
 			ret = PTR_ERR(blkg);
+			blkg_free(new_blkg);
 			goto fail_unlock;
 		}
 

Original file line number	Diff line number	Diff line change
`@@ -654,6 +654,7 @@ int blkg_conf_prep(struct blkcg blkcg, const struct blkcg_policy pol,`
`654`	`654`	`blkg = blkg_lookup_check(pos, pol, q);`
`655`	`655`	`if (IS_ERR(blkg)) {`
`656`	`656`	`ret = PTR_ERR(blkg);`
	`657`	`+ blkg_free(new_blkg);`
`657`	`658`	`goto fail_unlock;`
`658`	`659`	`}`
`659`	`660`