From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: 3.3.0-rc6-next20120305 net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage! Date: Wed, 07 Mar 2012 06:31:41 -0800 Message-ID: <1331130701.2474.61.camel@edumazet-laptop> References: <30475.1331126726@turing-police.cc.vt.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "David S. Miller" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Valdis.Kletnieks@vt.edu Return-path: In-Reply-To: <30475.1331126726@turing-police.cc.vt.edu> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Le mercredi 07 mars 2012 =C3=A0 08:25 -0500, Valdis.Kletnieks@vt.edu a =C3=A9crit : > Seen in my dmesg. Dell Latitude E6500. >=20 > [ 164.842511] > [ 164.842522] =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 > [ 164.842528] [ INFO: suspicious RCU usage. ] > [ 164.842538] 3.3.0-rc6-next-20120305 #1 Tainted: G O > [ 164.842544] ------------------------------- > [ 164.842552] net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_che= ck() usage! > [ 164.842559] > [ 164.842560] other info that might help us debug this: > [ 164.842563] > [ 164.842570] > [ 164.842571] rcu_scheduler_active =3D 1, debug_locks =3D 1 > [ 164.842579] 2 locks held by ksoftirqd/1/10: > [ 164.842586] #0: (&icsk->icsk_retransmit_timer){+.-...}, at: [] run_timer_softirq+0x17f/0x3e7 > [ 164.842620] #1: (slock-AF_INET){+.-...}, at: [= ] tcp_write_timer+0x1a/0x17b > [ 164.842649] > [ 164.842651] stack backtrace: > [ 164.842660] Pid: 10, comm: ksoftirqd/1 Tainted: G O 3.3.= 0-rc6-next-20120305 #1 > [ 164.842668] Call Trace: > [ 164.842685] [] lockdep_rcu_suspicious+0xec/0xf5 > [ 164.842698] [] tcp_md5_do_lookup+0x60/0xbe > [ 164.842710] [] tcp_v4_md5_lookup+0xe/0x10 > [ 164.842725] [] tcp_established_options+0x32/0x1= 10 > [ 164.842739] [] tcp_current_mss+0x50/0x6f > [ 164.842753] [] tcp_retransmit_skb+0xa9/0x510 > [ 164.842766] [] ? tcp_set_ca_state+0x23/0x2f > [ 164.842779] [] tcp_retransmit_timer+0x376/0x521 > [ 164.842791] [] tcp_write_timer+0x9f/0x17b > [ 164.842804] [] run_timer_softirq+0x257/0x3e7 > [ 164.842816] [] ? run_timer_softirq+0x17f/0x3e7 > [ 164.842828] [] ? tcp_retransmit_timer+0x521/0x5= 21 > [ 164.842843] [] __do_softirq+0x10a/0x25f > [ 164.842857] [] run_ksoftirqd+0xb5/0x200 > [ 164.842869] [] ? __do_softirq+0x25f/0x25f > [ 164.842884] [] kthread+0x86/0x8e > [ 164.842900] [] kernel_thread_helper+0x4/0x10 > [ 164.842914] [] ? retint_restore_args+0xe/0xe > [ 164.842928] [] ? flush_kthread_worker+0xcf/0xcf > [ 164.842941] [] ? gs_change+0xb/0xb >=20 Thanks for the report, I'll submit a patch in a few minutes