Messages in this thread |  | | | From | Miles Lane <> | | Subject | Re: 2.6.36-rc5-git1 -- include/linux/netpoll.h:67 invoked rcu_dereference_check() without protection! | | Date | Wed, 22 Sep 2010 13:43:26 -0400 |
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That worked for me. Thanks! Miles
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On Sep 22, 2010, at 10:27 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Le mercredi 22 septembre 2010 à 08:38 +0200, Eric Dumazet a écrit : >> Le mercredi 22 septembre 2010 à 00:22 -0400, Miles Lane a écrit : >>> [ INFO: suspicious rcu_dereference_check() usage. ] >>> --------------------------------------------------- >>> include/linux/netpoll.h:67 invoked rcu_dereference_check() without protection! >>> >>> other info that might help us debug this: >>> >>> >>> rcu_scheduler_active = 1, debug_locks = 1 >>> 1 lock held by avahi-daemon/1597: >>> #0: (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffffa03673b7>] >>> udpv6_sendmsg+0x6c2/0x9e6 [ipv6] >>> >>> stack backtrace: >>> Pid: 1597, comm: avahi-daemon Not tainted 2.6.36-rc5 #13 >>> Call Trace: >>> [<ffffffff810618d7>] lockdep_rcu_dereference+0x9d/0xa6 >>> [<ffffffff8129d543>] netif_rx+0x4e/0x1a7 >>> [<ffffffff8102fe4e>] ? get_parent_ip+0x11/0x41 >>> [<ffffffff8129d7e3>] netif_rx_ni+0x1e/0x58 >>> [<ffffffffa0352d50>] ip6_dev_loopback_xmit+0xc0/0xc7 [ipv6] >>> [<ffffffffa0352ef0>] ip6_finish_output2+0x199/0x3b6 [ipv6] >>> [<ffffffffa035401c>] ip6_finish_output+0xf0f/0xf27 [ipv6] >>> [<ffffffff8131e08a>] ? csum_partial_copy_from_user+0xb4/0xea >>> [<ffffffff812968a8>] ? csum_partial_copy_fromiovecend+0x178/0x1bd >>> [<ffffffffa035418c>] ip6_output+0x158/0x161 [ipv6] >>> [<ffffffff8102fe4e>] ? get_parent_ip+0x11/0x41 >>> [<ffffffffa035262d>] ip6_local_out+0x5d/0x62 [ipv6] >>> [<ffffffffa0352a98>] ip6_push_pending_frames+0x466/0x524 [ipv6] >>> [<ffffffffa0366a93>] udp_v6_push_pending_frames+0x27f/0x2fb [ipv6] >>> [<ffffffffa03673b7>] ? udpv6_sendmsg+0x6c2/0x9e6 [ipv6] >>> [<ffffffffa03674ba>] udpv6_sendmsg+0x7c5/0x9e6 [ipv6] >>> [<ffffffff812fb634>] ? inet_sendmsg+0x0/0x11f >>> [<ffffffff812fb746>] inet_sendmsg+0x112/0x11f >>> [<ffffffff812fb634>] ? inet_sendmsg+0x0/0x11f >>> [<ffffffff8128ca91>] sock_sendmsg+0xe7/0x108 >>> [<ffffffff810a4c3b>] ? might_fault+0x63/0xb3 >>> [<ffffffff810a4c84>] ? might_fault+0xac/0xb3 >>> [<ffffffff810a4c3b>] ? might_fault+0x63/0xb3 >>> [<ffffffff8128d346>] sys_sendmsg+0x24f/0x2d6 >>> [<ffffffff8102fe4e>] ? get_parent_ip+0x11/0x41 >>> [<ffffffff81031ef7>] ? sub_preempt_count+0x92/0xa6 >>> [<ffffffff810570ce>] ? __srcu_read_unlock+0x3b/0x57 >>> [<ffffffff81001f9c>] ? sysret_check+0x27/0x62 >>> [<ffffffff81001f6b>] system_call_fastpath+0x16/0x1b# >> >> Oh well. >> >> Thanks for the report. Could you please test following patch ? >> >> >> [PATCH] rcu: rcu_dereference_bh() is hard irq safe >> >> rcu_dereference_bh() doesnt know yet about hard irq being disabled, so >> lockdep can trigger in netpoll_rx() after commit f0f9deae9e7c4 (netpoll: >> Disable IRQ around RCU dereference in netpoll_rx) >> >> Reported-by: Miles Lane <miles.lane@gmail.com> >> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> >> --- >> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h >> index 9fbc54a..435c502 100644 >> --- a/include/linux/rcupdate.h >> +++ b/include/linux/rcupdate.h >> @@ -454,7 +454,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) >> * Makes rcu_dereference_check() do the dirty work. >> */ >> #define rcu_dereference_bh(p) \ >> - rcu_dereference_check(p, rcu_read_lock_bh_held()) >> + rcu_dereference_check(p, rcu_read_lock_bh_held() || in_irq()) > > oops, I meant irqs_disabled() here, not in_irq() > >> >> /** >> * rcu_dereference_sched - fetch RCU-protected pointer, checking for RCU-sched >> > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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