From: Cong Wang xiyou.wangcong@gmail.com
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@syzkaller.appspotmail.com Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together") Cc: Vlad Buslov vladbu@mellanox.com Cc: Jamal Hadi Salim jhs@mojatatu.com Cc: Jiri Pirko jiri@resnulli.us Signed-off-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net (cherry picked from commit 580e4273d7a883ececfefa692c1f96bdbacb99b5) Signed-off-by: George Kennedy george.kennedy@oracle.com --- net/sched/act_api.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 17e5cd9..75132d0 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -231,6 +231,8 @@ static int tcf_dump_walker(struct tcf_idrinfo *idrinfo, struct sk_buff *skb, index++; if (index < s_i) continue; + if (IS_ERR(p)) + continue;
if (jiffy_since && time_after(jiffy_since,