From: Cong Wang <xiyou.wangcong@xxxxxxxxx>
[ Upstream commit 580e4273d7a883ececfefa692c1f96bdbacb99b5 ]
Although we take RTNL on dump path, it is possible to
skip RTNL on insertion path. So the following race condition
is possible:
rtnl_lock() // no rtnl lock
mutex_lock(&idrinfo->lock);
// insert ERR_PTR(-EBUSY)
mutex_unlock(&idrinfo->lock);
tc_dump_action()
rtnl_unlock()
So we have to skip those temporary -EBUSY entries on dump path
too.
Reported-and-tested-by: syzbot+b47bc4f247856fb4d9e1@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together")
Cc: Vlad Buslov <vladbu@xxxxxxxxxxxx>
Cc: Jamal Hadi Salim <jhs@xxxxxxxxxxxx>
Cc: Jiri Pirko <jiri@xxxxxxxxxxx>
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/sched/act_api.c | 2 ++
1 file changed, 2 insertions(+)
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -231,6 +231,8 @@ static int tcf_dump_walker(struct tcf_id
index++;
if (index < s_i)
continue;
+ if (IS_ERR(p))
+ continue;
if (jiffy_since &&
time_after(jiffy_since,
