| Message ID | 20201002191334.14135-1-xiyou.wangcong@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [net] net_sched: check error pointer in tcf_dump_walker() | expand |
From: Cong Wang <xiyou.wangcong@gmail.com> Date: Fri, 2 Oct 2020 12:13:34 -0700 > 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> Applied and queued up for -stable.
diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 5612b336e18e..798430e1a79f 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -235,6 +235,8 @@ 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,
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> --- net/sched/act_api.c | 2 ++ 1 file changed, 2 insertions(+)