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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Valdis.Kletnieks@vt.edu
Cc: "David S. Miller" <davem@davemloft.net>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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	[thread overview]
Message-ID: <1331130701.2474.61.camel@edumazet-laptop> (raw)
In-Reply-To: <30475.1331126726@turing-police.cc.vt.edu>

Le mercredi 07 mars 2012 à 08:25 -0500, Valdis.Kletnieks@vt.edu a
écrit :
> Seen in my dmesg.  Dell Latitude E6500.
> 
> [  164.842511]
> [  164.842522] ===============================
> [  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_check() usage!
> [  164.842559]
> [  164.842560] other info that might help us debug this:
> [  164.842563]
> [  164.842570]
> [  164.842571] rcu_scheduler_active = 1, debug_locks = 1
> [  164.842579] 2 locks held by ksoftirqd/1/10:
> [  164.842586]  #0:  (&icsk->icsk_retransmit_timer){+.-...}, at: [<ffffffff81039086>] run_timer_softirq+0x17f/0x3e7
> [  164.842620]  #1:  (slock-AF_INET){+.-...}, at: [<ffffffff814b75b3>] 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]  [<ffffffff8106e6a2>] lockdep_rcu_suspicious+0xec/0xf5
> [  164.842698]  [<ffffffff814b7f40>] tcp_md5_do_lookup+0x60/0xbe
> [  164.842710]  [<ffffffff814b7fc0>] tcp_v4_md5_lookup+0xe/0x10
> [  164.842725]  [<ffffffff814b2eb5>] tcp_established_options+0x32/0x110
> [  164.842739]  [<ffffffff814b42d7>] tcp_current_mss+0x50/0x6f
> [  164.842753]  [<ffffffff814b5c50>] tcp_retransmit_skb+0xa9/0x510
> [  164.842766]  [<ffffffff814ab727>] ? tcp_set_ca_state+0x23/0x2f
> [  164.842779]  [<ffffffff814b73ee>] tcp_retransmit_timer+0x376/0x521
> [  164.842791]  [<ffffffff814b7638>] tcp_write_timer+0x9f/0x17b
> [  164.842804]  [<ffffffff8103915e>] run_timer_softirq+0x257/0x3e7
> [  164.842816]  [<ffffffff81039086>] ? run_timer_softirq+0x17f/0x3e7
> [  164.842828]  [<ffffffff814b7599>] ? tcp_retransmit_timer+0x521/0x521
> [  164.842843]  [<ffffffff81032207>] __do_softirq+0x10a/0x25f
> [  164.842857]  [<ffffffff81032411>] run_ksoftirqd+0xb5/0x200
> [  164.842869]  [<ffffffff8103235c>] ? __do_softirq+0x25f/0x25f
> [  164.842884]  [<ffffffff810499bd>] kthread+0x86/0x8e
> [  164.842900]  [<ffffffff815e2434>] kernel_thread_helper+0x4/0x10
> [  164.842914]  [<ffffffff815db41d>] ? retint_restore_args+0xe/0xe
> [  164.842928]  [<ffffffff81049937>] ? flush_kthread_worker+0xcf/0xcf
> [  164.842941]  [<ffffffff815e2430>] ? gs_change+0xb/0xb
> 

Thanks for the report, I'll submit a patch in a few minutes

  reply	other threads:[~2012-03-07 14:31 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-07 13:25 3.3.0-rc6-next20120305 net/ipv4/tcp_ipv4.c:930 suspicious rcu_dereference_check() usage! Valdis.Kletnieks
2012-03-07 14:31 ` Eric Dumazet [this message]
2012-03-07 14:45 ` Eric Dumazet
2012-03-07 20:16   ` David Miller

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