netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Cong Wang <xiyou.wangcong@gmail.com>
To: netdev@vger.kernel.org
Cc: Cong Wang <xiyou.wangcong@gmail.com>,
	syzbot+b47bc4f247856fb4d9e1@syzkaller.appspotmail.com,
	Vlad Buslov <vladbu@mellanox.com>,
	Jamal Hadi Salim <jhs@mojatatu.com>,
	Jiri Pirko <jiri@resnulli.us>
Subject: [Patch net] net_sched: check error pointer in tcf_dump_walker()
Date: Fri,  2 Oct 2020 12:13:34 -0700	[thread overview]
Message-ID: <20201002191334.14135-1-xiyou.wangcong@gmail.com> (raw)

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(+)

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,
-- 
2.28.0


             reply	other threads:[~2020-10-02 19:13 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-02 19:13 Cong Wang [this message]
2020-10-04 21:54 ` [Patch net] net_sched: check error pointer in tcf_dump_walker() David Miller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201002191334.14135-1-xiyou.wangcong@gmail.com \
    --to=xiyou.wangcong@gmail.com \
    --cc=jhs@mojatatu.com \
    --cc=jiri@resnulli.us \
    --cc=netdev@vger.kernel.org \
    --cc=syzbot+b47bc4f247856fb4d9e1@syzkaller.appspotmail.com \
    --cc=vladbu@mellanox.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).