* net/ipv4/route.c:645 suspicious rcu_dereference_check() usage!
@ 2012-09-10 8:44 chris
2012-09-10 9:46 ` Eric Dumazet
0 siblings, 1 reply; 2+ messages in thread
From: chris @ 2012-09-10 8:44 UTC (permalink / raw)
To: netdev; +Cc: linux-kernel
I've not seen this reported yet, so here's a warning that happens
occasionally:
[192979.475833]
[192979.475840] ===============================
[192979.475841] [ INFO: suspicious RCU usage. ]
[192979.475844] 3.6.0-rc2+ #33 Not tainted
[192979.475846] -------------------------------
[192979.475848] net/ipv4/route.c:645 suspicious rcu_dereference_check() usage!
[192979.475850]
[192979.475850] other info that might help us debug this:
[192979.475850]
[192979.475853]
[192979.475853] rcu_scheduler_active = 1, debug_locks = 0
[192979.475856] 2 locks held by firefox-bin/4634:
[192979.475858] #0: (slock-AF_INET){+.-...}, at: [<ffffffff814261b4>] release_sock+0x34/0x1e0
[192979.475870] #1: (fnhe_lock){+.-...}, at: [<ffffffff81461c94>] update_or_create_fnhe.isra.30+0x44/0x480
[192979.475878]
[192979.475878] stack backtrace:
[192979.475881] Pid: 4634, comm: firefox-bin Not tainted 3.6.0-rc2+ #33
[192979.475883] Call Trace:
[192979.475891] [<ffffffff810903cd>] lockdep_rcu_suspicious+0xfd/0x130
[192979.475895] [<ffffffff81461e8e>] update_or_create_fnhe.isra.30+0x23e/0x480
[192979.475899] [<ffffffff814624ba>] __ip_rt_update_pmtu.isra.31+0x6a/0xb0
[192979.475903] [<ffffffff81465038>] ip_rt_update_pmtu+0x48/0xd0
[192979.475907] [<ffffffff814759b1>] inet_csk_update_pmtu+0x31/0x80
[192979.475912] [<ffffffff8148b663>] tcp_v4_mtu_reduced+0x33/0xd0
[192979.475915] [<ffffffff814888be>] tcp_release_cb+0x5e/0xb0
[192979.475919] [<ffffffff81426289>] release_sock+0x109/0x1e0
[192979.475922] [<ffffffff81479037>] tcp_sendmsg+0x527/0x1030
[192979.475927] [<ffffffff814a4d9d>] inet_sendmsg+0xed/0x240
[192979.475931] [<ffffffff814a4cb0>] ? inet_autobind+0x70/0x70
[192979.475934] [<ffffffff81424e8a>] ? sock_update_classid+0xaa/0x370
[192979.475937] [<ffffffff81424eb8>] ? sock_update_classid+0xd8/0x370
[192979.475941] [<ffffffff8141ee1b>] sock_sendmsg+0xab/0xe0
[192979.475946] [<ffffffff814222be>] sys_sendto+0x11e/0x160
[192979.475951] [<ffffffff8153e547>] ? sysret_check+0x1b/0x56
[192979.475956] [<ffffffff8125849e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[192979.475960] [<ffffffff8153e522>] system_call_fastpath+0x16/0x1b
--
Chris Wilson, Intel Open Source Technology Centre
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: net/ipv4/route.c:645 suspicious rcu_dereference_check() usage!
2012-09-10 8:44 net/ipv4/route.c:645 suspicious rcu_dereference_check() usage! chris
@ 2012-09-10 9:46 ` Eric Dumazet
0 siblings, 0 replies; 2+ messages in thread
From: Eric Dumazet @ 2012-09-10 9:46 UTC (permalink / raw)
To: chris; +Cc: netdev, linux-kernel
On Mon, 2012-09-10 at 09:44 +0100, chris@chris-wilson.co.uk wrote:
> I've not seen this reported yet, so here's a warning that happens
> occasionally:
>
> [192979.475833]
> [192979.475840] ===============================
> [192979.475841] [ INFO: suspicious RCU usage. ]
> [192979.475844] 3.6.0-rc2+ #33 Not tainted
> [192979.475846] -------------------------------
> [192979.475848] net/ipv4/route.c:645 suspicious rcu_dereference_check() usage!
> [192979.475850]
> [192979.475850] other info that might help us debug this:
> [192979.475850]
> [192979.475853]
> [192979.475853] rcu_scheduler_active = 1, debug_locks = 0
> [192979.475856] 2 locks held by firefox-bin/4634:
> [192979.475858] #0: (slock-AF_INET){+.-...}, at: [<ffffffff814261b4>] release_sock+0x34/0x1e0
> [192979.475870] #1: (fnhe_lock){+.-...}, at: [<ffffffff81461c94>] update_or_create_fnhe.isra.30+0x44/0x480
> [192979.475878]
> [192979.475878] stack backtrace:
> [192979.475881] Pid: 4634, comm: firefox-bin Not tainted 3.6.0-rc2+ #33
> [192979.475883] Call Trace:
> [192979.475891] [<ffffffff810903cd>] lockdep_rcu_suspicious+0xfd/0x130
> [192979.475895] [<ffffffff81461e8e>] update_or_create_fnhe.isra.30+0x23e/0x480
> [192979.475899] [<ffffffff814624ba>] __ip_rt_update_pmtu.isra.31+0x6a/0xb0
> [192979.475903] [<ffffffff81465038>] ip_rt_update_pmtu+0x48/0xd0
> [192979.475907] [<ffffffff814759b1>] inet_csk_update_pmtu+0x31/0x80
> [192979.475912] [<ffffffff8148b663>] tcp_v4_mtu_reduced+0x33/0xd0
> [192979.475915] [<ffffffff814888be>] tcp_release_cb+0x5e/0xb0
> [192979.475919] [<ffffffff81426289>] release_sock+0x109/0x1e0
> [192979.475922] [<ffffffff81479037>] tcp_sendmsg+0x527/0x1030
> [192979.475927] [<ffffffff814a4d9d>] inet_sendmsg+0xed/0x240
> [192979.475931] [<ffffffff814a4cb0>] ? inet_autobind+0x70/0x70
> [192979.475934] [<ffffffff81424e8a>] ? sock_update_classid+0xaa/0x370
> [192979.475937] [<ffffffff81424eb8>] ? sock_update_classid+0xd8/0x370
> [192979.475941] [<ffffffff8141ee1b>] sock_sendmsg+0xab/0xe0
> [192979.475946] [<ffffffff814222be>] sys_sendto+0x11e/0x160
> [192979.475951] [<ffffffff8153e547>] ? sysret_check+0x1b/0x56
> [192979.475956] [<ffffffff8125849e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
> [192979.475960] [<ffffffff8153e522>] system_call_fastpath+0x16/0x1b
>
Probably already fixed in commit c5ae7d41927d (ipv4: must use rcu
protection while calling fib_lookup)
3.6.0-rc2 is quite old for a dev kernel ;)
Thanks
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