From: Jason Wang <jasowang@redhat.com>
To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: mst@redhat.com, Jason Wang <jasowang@redhat.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
Willem de Bruijn <willemb@google.com>
Subject: [PATCH net-next] tuntap: fix possible deadlock when fail to register netdev
Date: Fri, 8 Dec 2017 10:54:15 +0800 [thread overview]
Message-ID: <1512701655-18751-1-git-send-email-jasowang@redhat.com> (raw)
Private destructor could be called when register_netdev() fail with
rtnl lock held. This will lead deadlock in tun_free_netdev() who tries
to hold rtnl_lock. Fixing this by switching to use spinlock to
synchronize.
Fixes: 96f84061620c ("tun: add eBPF based queue selection method")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/net/tun.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 787cc35..f7ccd79 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -2050,8 +2050,11 @@ static int __tun_set_steering_ebpf(struct tun_struct *tun,
new->prog = prog;
}
- old = rtnl_dereference(tun->steering_prog);
+ spin_lock(&tun->lock);
+ old = rcu_dereference_protected(tun->steering_prog,
+ lock_is_held(&tun->lock));
rcu_assign_pointer(tun->steering_prog, new);
+ spin_unlock(&tun->lock);
if (old)
call_rcu(&old->rcu, tun_steering_prog_free);
@@ -2067,9 +2070,7 @@ static void tun_free_netdev(struct net_device *dev)
free_percpu(tun->pcpu_stats);
tun_flow_uninit(tun);
security_tun_dev_free_security(tun->security);
- rtnl_lock();
__tun_set_steering_ebpf(tun, NULL);
- rtnl_unlock();
}
static void tun_setup(struct net_device *dev)
--
2.7.4
next reply other threads:[~2017-12-08 2:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-08 2:54 Jason Wang [this message]
2017-12-08 3:11 ` [PATCH net-next] tuntap: fix possible deadlock when fail to register netdev Eric Dumazet
2017-12-08 3:27 ` Jason Wang
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=1512701655-18751-1-git-send-email-jasowang@redhat.com \
--to=jasowang@redhat.com \
--cc=eric.dumazet@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mst@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=willemb@google.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).