[PATCH net] cls_flower: Fix incorrect idr release when failing to modify rule

[PATCH net] cls_flower: Fix incorrect idr release when failing to modify rule

[Paul Blakey]

When we fail to modify a rule, we incorrectly release the idr handle
of the unmodified old rule.

Fix that by checking if we need to release it.

Fixes: fe2502e49b58 ("net_sched: remove cls_flower idr on failure")
Reported-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Paul Blakey <paulb@mellanox.com>
---
 net/sched/cls_flower.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index d964e60..c79f6e7 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -977,7 +977,7 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
 	return 0;
 
 errout_idr:
-	if (fnew->handle)
+	if (!fold)
 		idr_remove(&head->handle_idr, fnew->handle);
 errout:
 	tcf_exts_destroy(&fnew->exts);
-- 
2.7.4

Re: [PATCH net] cls_flower: Fix incorrect idr release when failing to modify rule

[David Miller]

From: Paul Blakey <paulb@mellanox.com>
Date: Wed, 30 May 2018 11:29:15 +0300

> When we fail to modify a rule, we incorrectly release the idr handle
> of the unmodified old rule.
> 
> Fix that by checking if we need to release it.
> 
> Fixes: fe2502e49b58 ("net_sched: remove cls_flower idr on failure")
> Reported-by: Vlad Buslov <vladbu@mellanox.com>
> Reviewed-by: Roi Dayan <roid@mellanox.com>
> Acked-by: Jiri Pirko <jiri@mellanox.com>
> Signed-off-by: Paul Blakey <paulb@mellanox.com>

Applied and queued up for -stable.