From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: 2.6.39-rc6-mmotm0506 - another lockdep splat (networking this time) Date: Tue, 10 May 2011 04:23:08 +0200 Message-ID: <1304994188.3050.17.camel@edumazet-laptop> References: <6954.1304989523@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Andrew Morton , "David S. Miller" , linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: Valdis.Kletnieks@vt.edu Return-path: In-Reply-To: <6954.1304989523@localhost> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Le lundi 09 mai 2011 =C3=A0 21:05 -0400, Valdis.Kletnieks@vt.edu a =C3=A9= crit : > Seen during boot this afternoon: >=20 > [ 43.309549]=20 > [ 43.309550] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D > [ 43.309553] [ INFO: suspicious rcu_dereference_check() usage. ] > [ 43.309555] --------------------------------------------------- > [ 43.309558] include/linux/inetdevice.h:226 invoked rcu_dereference= _check() without protection! > [ 43.309560]=20 > [ 43.309561] other info that might help us debug this: > [ 43.309561]=20 > [ 43.309563]=20 > [ 43.309564] rcu_scheduler_active =3D 1, debug_locks =3D 1 > [ 43.309567] 2 locks held by ip/1193: > [ 43.309568] #0: (nlk->cb_mutex){+.+...}, at: [= ] netlink_dump+0x45/0x1d0 > [ 43.309579] #1: (rcu_read_lock){.+.+..}, at: [= ] rtnl_dump_ifinfo+0x0/0x156 strange : rcu_read_lock() is correctly held at this point > [ 43.309587]=20 > [ 43.309587] stack backtrace: > [ 43.309590] Pid: 1193, comm: ip Not tainted 2.6.39-rc6-mmotm0506 #= 1 > [ 43.309592] Call Trace: > [ 43.309599] [] lockdep_rcu_dereference+0x9a/0xa= 2 > [ 43.309604] [] __in_dev_get_rtnl+0x3c/0x47 > [ 43.309607] [] inet_fill_link_af+0x12/0x5b > [ 43.309611] [] rtnl_fill_ifinfo+0x665/0x710 > [ 43.309616] [] rtnl_dump_ifinfo+0xbd/0x156 > [ 43.309620] [] netlink_dump+0x5f/0x1d0 > [ 43.309624] [] ? consume_skb+0x8a/0x8f > [ 43.309628] [] netlink_recvmsg+0x1dd/0x31d > [ 43.309632] [] ? rcu_read_unlock+0x21/0x23 > [ 43.309636] [] sock_recvmsg+0xed/0x112 > [ 43.309641] [] ? might_fault+0x4e/0x9e > [ 43.309645] [] ? __lock_release+0x93/0x9c > [ 43.309649] [] ? might_fault+0x4e/0x9e > [ 43.309652] [] ? might_fault+0x97/0x9e > [ 43.309656] [] ? copy_from_user+0x3c/0x44 > [ 43.309660] [] __sys_recvmsg+0x16c/0x224 > [ 43.309665] [] ? up_read+0x23/0x27 > [ 43.309669] [] ? arch_local_irq_save+0x9/0xc > [ 43.309673] [] ? fcheck_files+0xb4/0xeb > [ 43.309676] [] ? fget_light+0x35/0x96 > [ 43.309680] [] sys_recvmsg+0x3d/0x5b > [ 43.309686] [] system_call_fastpath+0x16/0x1b > [ 44.437679] e1000e 0000:00:19.0: irq 46 for MSI/MSI-X > [ 44.488363] e1000e 0000:00:19.0: irq 46 for MSI/MSI-X > [ 44.494680] ADDRCONF(NETDEV_UP): eth0: link is not ready >=20 >=20 Thanks for the report, I am taking a look how to fix this. I am testing following patch, I'll provide an official one when validated. diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index cd9ca08..6b1eb92 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1369,7 +1369,7 @@ errout: =20 static size_t inet_get_link_af_size(const struct net_device *dev) { - struct in_device *in_dev =3D __in_dev_get_rtnl(dev); + struct in_device *in_dev =3D __in_dev_get_rcu(dev); =20 if (!in_dev) return 0; @@ -1379,7 +1379,7 @@ static size_t inet_get_link_af_size(const struct = net_device *dev) =20 static int inet_fill_link_af(struct sk_buff *skb, const struct net_dev= ice *dev) { - struct in_device *in_dev =3D __in_dev_get_rtnl(dev); + struct in_device *in_dev =3D __in_dev_get_rcu(dev); struct nlattr *nla; int i; =20