* iw lockdep warning on wireless-testing
@ 2008-06-24 7:39 Zhu Yi
2008-06-24 8:59 ` Johannes Berg
0 siblings, 1 reply; 4+ messages in thread
From: Zhu Yi @ 2008-06-24 7:39 UTC (permalink / raw)
To: linux-wireless
Hi,
I begin to see below lockdep warning on wireless-testing when I use iw
to create a monitor interface with iwl4965. Any clues?
Thanks,
-yi
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.26-rc6-wl #57
-------------------------------------------------------
iw/2763 is trying to acquire lock:
(genl_mutex){--..}, at: [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
but task is already holding lock:
(nlk->cb_mutex){--..}, at: [<ffffffff812137c8>] netlink_dump+0x40/0x19d
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (nlk->cb_mutex){--..}:
[<ffffffff810518cb>] __lock_acquire+0xa4c/0xc28
[<ffffffff81215774>] netlink_dump_start+0xd9/0x169
[<ffffffff81051e5d>] lock_acquire+0x51/0x6c
[<ffffffff81215774>] netlink_dump_start+0xd9/0x169
[<ffffffff8104eab1>] debug_mutex_lock_common+0x16/0x23
[<ffffffff8127c622>] mutex_lock_nested+0xde/0x23f
[<ffffffff81215774>] netlink_dump_start+0xd9/0x169
[<ffffffff81216d7e>] genl_rcv_msg+0xae/0x14b
[<ffffffff8127c774>] mutex_lock_nested+0x230/0x23f
[<ffffffff81216cd0>] genl_rcv_msg+0x0/0x14b
[<ffffffff8121483a>] netlink_rcv_skb+0x34/0x7c
[<ffffffff81216fe1>] genl_rcv+0x21/0x30
[<ffffffff812145ec>] netlink_unicast+0x1f7/0x287
[<ffffffff811f7eb7>] __alloc_skb+0x84/0x132
[<ffffffff81214d60>] netlink_sendmsg+0x274/0x287
[<ffffffff811f1b49>] sock_sendmsg+0xe2/0xff
[<ffffffff8104582f>] autoremove_wake_function+0x0/0x2e
[<ffffffff81050878>] mark_held_locks+0x49/0x67
[<ffffffff811f1d7d>] sys_sendmsg+0x217/0x28a
[<ffffffff8107de49>] __do_fault+0x35d/0x3a5
[<ffffffff8100bf10>] tracesys+0xd5/0xda
[<ffffffffffffffff>] 0xffffffffffffffff
-> #0 (genl_mutex){--..}:
[<ffffffff81050226>] print_circular_bug_header+0xc8/0xcf
[<ffffffff810517d0>] __lock_acquire+0x951/0xc28
[<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
[<ffffffff81051e5d>] lock_acquire+0x51/0x6c
[<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
[<ffffffff8104eab1>] debug_mutex_lock_common+0x16/0x23
[<ffffffff8127c622>] mutex_lock_nested+0xde/0x23f
[<ffffffff81050a10>] trace_hardirqs_on+0xf3/0x117
[<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
[<ffffffff812137e3>] netlink_dump+0x5b/0x19d
[<ffffffff81214ef3>] netlink_recvmsg+0x180/0x2a8
[<ffffffff811f1a48>] sock_recvmsg+0xf0/0x10f
[<ffffffff8104582f>] autoremove_wake_function+0x0/0x2e
[<ffffffff81050878>] mark_held_locks+0x49/0x67
[<ffffffff811f295c>] sys_recvmsg+0x15c/0x254
[<ffffffff81067ac3>] audit_syscall_entry+0x12d/0x160
[<ffffffff8127d6da>] trace_hardirqs_on_thunk+0x35/0x3a
[<ffffffff8100bf10>] tracesys+0xd5/0xda
[<ffffffffffffffff>] 0xffffffffffffffff
other info that might help us debug this:
1 lock held by iw/2763:
#0: (nlk->cb_mutex){--..}, at: [<ffffffff812137c8>] netlink_dump
+0x40/0x19d
stack backtrace:
Pid: 2763, comm: iw Not tainted 2.6.26-rc6-wl #57
Call Trace:
[<ffffffff8104fe63>] print_circular_bug_tail+0x69/0x72
[<ffffffff81050226>] print_circular_bug_header+0xc8/0xcf
[<ffffffff810517d0>] __lock_acquire+0x951/0xc28
[<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
[<ffffffff81051e5d>] lock_acquire+0x51/0x6c
[<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
[<ffffffff8104eab1>] debug_mutex_lock_common+0x16/0x23
[<ffffffff8127c622>] mutex_lock_nested+0xde/0x23f
[<ffffffff81050a10>] trace_hardirqs_on+0xf3/0x117
[<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
[<ffffffff812137e3>] netlink_dump+0x5b/0x19d
[<ffffffff81214ef3>] netlink_recvmsg+0x180/0x2a8
[<ffffffff811f1a48>] sock_recvmsg+0xf0/0x10f
[<ffffffff8104582f>] autoremove_wake_function+0x0/0x2e
[<ffffffff81050878>] mark_held_locks+0x49/0x67
[<ffffffff811f295c>] sys_recvmsg+0x15c/0x254
[<ffffffff81067ac3>] audit_syscall_entry+0x12d/0x160
[<ffffffff8127d6da>] trace_hardirqs_on_thunk+0x35/0x3a
[<ffffffff8100bf10>] tracesys+0xd5/0xda
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: iw lockdep warning on wireless-testing
2008-06-24 7:39 iw lockdep warning on wireless-testing Zhu Yi
@ 2008-06-24 8:59 ` Johannes Berg
2008-06-24 9:05 ` Zhu Yi
0 siblings, 1 reply; 4+ messages in thread
From: Johannes Berg @ 2008-06-24 8:59 UTC (permalink / raw)
To: Zhu Yi; +Cc: linux-wireless, Thomas Graf, netdev
[-- Attachment #1: Type: text/plain, Size: 4744 bytes --]
Hi,
> I begin to see below lockdep warning on wireless-testing when I use iw
> to create a monitor interface with iwl4965. Any clues?
Yeah I've seen that reported too, but I think it's in genetlink.
> =======================================================
> [ INFO: possible circular locking dependency detected ]
> 2.6.26-rc6-wl #57
> -------------------------------------------------------
> iw/2763 is trying to acquire lock:
> (genl_mutex){--..}, at: [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
>
> but task is already holding lock:
> (nlk->cb_mutex){--..}, at: [<ffffffff812137c8>] netlink_dump+0x40/0x19d
>
> which lock already depends on the new lock.
None of those is anything nl80211 has influence over, afaict.
>
> the existing dependency chain (in reverse order) is:
>
> -> #1 (nlk->cb_mutex){--..}:
> [<ffffffff810518cb>] __lock_acquire+0xa4c/0xc28
> [<ffffffff81215774>] netlink_dump_start+0xd9/0x169
> [<ffffffff81051e5d>] lock_acquire+0x51/0x6c
> [<ffffffff81215774>] netlink_dump_start+0xd9/0x169
> [<ffffffff8104eab1>] debug_mutex_lock_common+0x16/0x23
> [<ffffffff8127c622>] mutex_lock_nested+0xde/0x23f
> [<ffffffff81215774>] netlink_dump_start+0xd9/0x169
> [<ffffffff81216d7e>] genl_rcv_msg+0xae/0x14b
> [<ffffffff8127c774>] mutex_lock_nested+0x230/0x23f
> [<ffffffff81216cd0>] genl_rcv_msg+0x0/0x14b
> [<ffffffff8121483a>] netlink_rcv_skb+0x34/0x7c
> [<ffffffff81216fe1>] genl_rcv+0x21/0x30
> [<ffffffff812145ec>] netlink_unicast+0x1f7/0x287
> [<ffffffff811f7eb7>] __alloc_skb+0x84/0x132
> [<ffffffff81214d60>] netlink_sendmsg+0x274/0x287
> [<ffffffff811f1b49>] sock_sendmsg+0xe2/0xff
> [<ffffffff8104582f>] autoremove_wake_function+0x0/0x2e
> [<ffffffff81050878>] mark_held_locks+0x49/0x67
> [<ffffffff811f1d7d>] sys_sendmsg+0x217/0x28a
> [<ffffffff8107de49>] __do_fault+0x35d/0x3a5
> [<ffffffff8100bf10>] tracesys+0xd5/0xda
> [<ffffffffffffffff>] 0xffffffffffffffff
>
> -> #0 (genl_mutex){--..}:
> [<ffffffff81050226>] print_circular_bug_header+0xc8/0xcf
> [<ffffffff810517d0>] __lock_acquire+0x951/0xc28
> [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
> [<ffffffff81051e5d>] lock_acquire+0x51/0x6c
> [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
> [<ffffffff8104eab1>] debug_mutex_lock_common+0x16/0x23
> [<ffffffff8127c622>] mutex_lock_nested+0xde/0x23f
> [<ffffffff81050a10>] trace_hardirqs_on+0xf3/0x117
> [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
> [<ffffffff812137e3>] netlink_dump+0x5b/0x19d
> [<ffffffff81214ef3>] netlink_recvmsg+0x180/0x2a8
> [<ffffffff811f1a48>] sock_recvmsg+0xf0/0x10f
> [<ffffffff8104582f>] autoremove_wake_function+0x0/0x2e
> [<ffffffff81050878>] mark_held_locks+0x49/0x67
> [<ffffffff811f295c>] sys_recvmsg+0x15c/0x254
> [<ffffffff81067ac3>] audit_syscall_entry+0x12d/0x160
> [<ffffffff8127d6da>] trace_hardirqs_on_thunk+0x35/0x3a
> [<ffffffff8100bf10>] tracesys+0xd5/0xda
> [<ffffffffffffffff>] 0xffffffffffffffff
>
> other info that might help us debug this:
>
> 1 lock held by iw/2763:
> #0: (nlk->cb_mutex){--..}, at: [<ffffffff812137c8>] netlink_dump
> +0x40/0x19d
>
> stack backtrace:
> Pid: 2763, comm: iw Not tainted 2.6.26-rc6-wl #57
>
> Call Trace:
> [<ffffffff8104fe63>] print_circular_bug_tail+0x69/0x72
> [<ffffffff81050226>] print_circular_bug_header+0xc8/0xcf
> [<ffffffff810517d0>] __lock_acquire+0x951/0xc28
> [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
> [<ffffffff81051e5d>] lock_acquire+0x51/0x6c
> [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
> [<ffffffff8104eab1>] debug_mutex_lock_common+0x16/0x23
> [<ffffffff8127c622>] mutex_lock_nested+0xde/0x23f
> [<ffffffff81050a10>] trace_hardirqs_on+0xf3/0x117
> [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
> [<ffffffff812137e3>] netlink_dump+0x5b/0x19d
> [<ffffffff81214ef3>] netlink_recvmsg+0x180/0x2a8
> [<ffffffff811f1a48>] sock_recvmsg+0xf0/0x10f
> [<ffffffff8104582f>] autoremove_wake_function+0x0/0x2e
> [<ffffffff81050878>] mark_held_locks+0x49/0x67
> [<ffffffff811f295c>] sys_recvmsg+0x15c/0x254
> [<ffffffff81067ac3>] audit_syscall_entry+0x12d/0x160
> [<ffffffff8127d6da>] trace_hardirqs_on_thunk+0x35/0x3a
> [<ffffffff8100bf10>] tracesys+0xd5/0xda
>
>
>
> --
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: iw lockdep warning on wireless-testing
2008-06-24 8:59 ` Johannes Berg
@ 2008-06-24 9:05 ` Zhu Yi
2008-06-24 15:03 ` Jarek Poplawski
0 siblings, 1 reply; 4+ messages in thread
From: Zhu Yi @ 2008-06-24 9:05 UTC (permalink / raw)
To: Johannes Berg; +Cc: linux-wireless, Thomas Graf, netdev
On Tue, 2008-06-24 at 10:59 +0200, Johannes Berg wrote:
> > [ INFO: possible circular locking dependency detected ]
> > 2.6.26-rc6-wl #57
> > -------------------------------------------------------
> > iw/2763 is trying to acquire lock:
> > (genl_mutex){--..}, at: [<ffffffff81216e4c>] ctrl_dumpfamily
> +0x31/0xf7
> >
> > but task is already holding lock:
> > (nlk->cb_mutex){--..}, at: [<ffffffff812137c8>] netlink_dump
> +0x40/0x19d
> >
> > which lock already depends on the new lock.
>
> None of those is anything nl80211 has influence over, afaict.
Agreed. I can follow the two scenarios below. Apparently it's a ABBA
locking issue. Just don't know which should be the correct sequence for
using with the two locks.
Thanks,
-yi
> > the existing dependency chain (in reverse order) is:
> >
> > -> #1 (nlk->cb_mutex){--..}:
> > [<ffffffff810518cb>] __lock_acquire+0xa4c/0xc28
> > [<ffffffff81215774>] netlink_dump_start+0xd9/0x169
> > [<ffffffff81051e5d>] lock_acquire+0x51/0x6c
> > [<ffffffff81215774>] netlink_dump_start+0xd9/0x169
> > [<ffffffff8104eab1>] debug_mutex_lock_common+0x16/0x23
> > [<ffffffff8127c622>] mutex_lock_nested+0xde/0x23f
> > [<ffffffff81215774>] netlink_dump_start+0xd9/0x169
> > [<ffffffff81216d7e>] genl_rcv_msg+0xae/0x14b
> > [<ffffffff8127c774>] mutex_lock_nested+0x230/0x23f
> > [<ffffffff81216cd0>] genl_rcv_msg+0x0/0x14b
> > [<ffffffff8121483a>] netlink_rcv_skb+0x34/0x7c
> > [<ffffffff81216fe1>] genl_rcv+0x21/0x30
> > [<ffffffff812145ec>] netlink_unicast+0x1f7/0x287
> > [<ffffffff811f7eb7>] __alloc_skb+0x84/0x132
> > [<ffffffff81214d60>] netlink_sendmsg+0x274/0x287
> > [<ffffffff811f1b49>] sock_sendmsg+0xe2/0xff
> > [<ffffffff8104582f>] autoremove_wake_function+0x0/0x2e
> > [<ffffffff81050878>] mark_held_locks+0x49/0x67
> > [<ffffffff811f1d7d>] sys_sendmsg+0x217/0x28a
> > [<ffffffff8107de49>] __do_fault+0x35d/0x3a5
> > [<ffffffff8100bf10>] tracesys+0xd5/0xda
> > [<ffffffffffffffff>] 0xffffffffffffffff
> >
> > -> #0 (genl_mutex){--..}:
> > [<ffffffff81050226>] print_circular_bug_header+0xc8/0xcf
> > [<ffffffff810517d0>] __lock_acquire+0x951/0xc28
> > [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
> > [<ffffffff81051e5d>] lock_acquire+0x51/0x6c
> > [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
> > [<ffffffff8104eab1>] debug_mutex_lock_common+0x16/0x23
> > [<ffffffff8127c622>] mutex_lock_nested+0xde/0x23f
> > [<ffffffff81050a10>] trace_hardirqs_on+0xf3/0x117
> > [<ffffffff81216e4c>] ctrl_dumpfamily+0x31/0xf7
> > [<ffffffff812137e3>] netlink_dump+0x5b/0x19d
> > [<ffffffff81214ef3>] netlink_recvmsg+0x180/0x2a8
> > [<ffffffff811f1a48>] sock_recvmsg+0xf0/0x10f
> > [<ffffffff8104582f>] autoremove_wake_function+0x0/0x2e
> > [<ffffffff81050878>] mark_held_locks+0x49/0x67
> > [<ffffffff811f295c>] sys_recvmsg+0x15c/0x254
> > [<ffffffff81067ac3>] audit_syscall_entry+0x12d/0x160
> > [<ffffffff8127d6da>] trace_hardirqs_on_thunk+0x35/0x3a
> > [<ffffffff8100bf10>] tracesys+0xd5/0xda
> > [<ffffffffffffffff>] 0xffffffffffffffff
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: iw lockdep warning on wireless-testing
2008-06-24 9:05 ` Zhu Yi
@ 2008-06-24 15:03 ` Jarek Poplawski
0 siblings, 0 replies; 4+ messages in thread
From: Jarek Poplawski @ 2008-06-24 15:03 UTC (permalink / raw)
To: linux-wireless; +Cc: netdev
Zhu Yi wrote, On 06/24/2008 11:05 AM:
> On Tue, 2008-06-24 at 10:59 +0200, Johannes Berg wrote:
>>> [ INFO: possible circular locking dependency detected ]
>>> 2.6.26-rc6-wl #57
>>> -------------------------------------------------------
>>> iw/2763 is trying to acquire lock:
>>> (genl_mutex){--..}, at: [<ffffffff81216e4c>] ctrl_dumpfamily
>> +0x31/0xf7
>>> but task is already holding lock:
>>> (nlk->cb_mutex){--..}, at: [<ffffffff812137c8>] netlink_dump
>> +0x40/0x19d
>>> which lock already depends on the new lock.
>> None of those is anything nl80211 has influence over, afaict.
>
> Agreed. I can follow the two scenarios below. Apparently it's a ABBA
> locking issue. Just don't know which should be the correct sequence for
> using with the two locks.
>
It should be fixed by this patch:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=6d1a3fb567a728d31474636e167c324702a0c38b
Regards,
Jarek P.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2008-06-24 7:39 iw lockdep warning on wireless-testing Zhu Yi
2008-06-24 8:59 ` Johannes Berg
2008-06-24 9:05 ` Zhu Yi
2008-06-24 15:03 ` Jarek Poplawski
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