From mboxrd@z Thu Jan 1 00:00:00 1970 From: Valdis.Kletnieks@vt.edu Subject: Re: mmotm 2010-04-28 - RCU whinges Date: Mon, 03 May 2010 11:29:50 -0400 Message-ID: <5112.1272900590@localhost> References: <201004290021.o3T0L04Y028017@imap1.linux-foundation.org> <5702.1272822394@localhost> <1272865137.2173.179.camel@edumazet-laptop> <5933.1272897014@localhost> <1272898726.2226.47.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1272900590_4168P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Cc: Andrew Morton , Peter Zijlstra , Patrick McHardy , "David S. Miller" , linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, netdev@vger.kernel.org, "Paul E. McKenney" To: Eric Dumazet Return-path: In-Reply-To: Your message of "Mon, 03 May 2010 16:58:46 +0200." <1272898726.2226.47.camel@edumazet-laptop> Sender: linux-kernel-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org --==_Exmh_1272900590_4168P Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable On Mon, 03 May 2010 16:58:46 +0200, Eric Dumazet said: > Le lundi 03 mai 2010 =E0 10:30 -0400, Valdis.Kletnieks=40vt.edu a =E9cr= it : > > =5B 9.129872=5D net/netfilter/nf_log.c:55 invoked rcu_dereference_= check() without protection=21 > Thanks for the report =21 >=20 > =5BPATCH=5D net: nf_log RCU fixes >=20 > nf_log_register() and nf_log_unregister() use a mutex to have exclusive= > access to nf_logers=5B=5D. Use appropriate rcu_dereference_protected() > lockdep annotation. Confirming that one fixed. Now it lives a whole 36 seconds before whingi= ng: =5B 35.328729=5D =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 =5B 35.328803=5D =5B INFO: suspicious rcu_dereference_check() usage. = =5D =5B 35.328837=5D --------------------------------------------------- =5B 35.328872=5D net/ipv6/addrconf.c:2977 invoked rcu_dereference_check= () without protection=21 =5B 35.328926=5D=20 =5B 35.328927=5D other info that might help us debug this: =5B 35.328928=5D=20 =5B 35.329016=5D=20 =5B 35.329016=5D rcu_scheduler_active =3D 1, debug_locks =3D 0 =5B 35.329089=5D 2 locks held by ifconfig/2680: =5B 35.329120=5D =230: (&p->lock)=7B+.+.+.=7D, at: =5B=5D seq_read+0x3a/0x42d =5B 35.329217=5D =231: (rcu_read_lock_bh)=7B.+....=7D, at: =5B=5D rcu_read_lock_bh+0x0/0x35 =5B 35.329322=5D=20 =5B 35.329323=5D stack backtrace: =5B 35.329380=5D Pid: 2680, comm: ifconfig Tainted: G W 2.6.34= -rc5-mmotm0428 =233 =5B 35.329439=5D Call Trace: =5B 35.329471=5D =5B=5D lockdep_rcu_dereference+0xaa= /0xb2 =5B 35.329514=5D =5B=5D if6_get_next+0x34/0x6d =5B 35.329554=5D =5B=5D if6_seq_next+0x11/0x18 =5B 35.329595=5D =5B=5D seq_read+0x305/0x42d =5B 35.329635=5D =5B=5D ? seq_read+0x0/0x42d =5B 35.329676=5D =5B=5D proc_reg_read+0x8d/0xac =5B 35.329717=5D =5B=5D vfs_read+0xe0/0x140 =5B 35.329758=5D =5B=5D sys_read+0x45/0x69 =5B 35.329799=5D =5B=5D system_call_fastpath+0x16/0x= 1b Maybe I need to go and stick the =22RCU whinge multiple times=22 patch on= this kernel and get it over with. :) --==_Exmh_1272900590_4168P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFL3uvucC3lWbTT17ARAuZxAKCk9ywIgNhKPIKqFAu0ppWMYSZnqACg63/W yGUHCD1JYszl3WwoVGHmh6g= =H+GJ -----END PGP SIGNATURE----- --==_Exmh_1272900590_4168P--