Re: [PATCH] netdev: Fix sleeping inside wait event

From: David Miller
Date: Wed Oct 29 2014 - 13:37:55 EST


From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Wed, 29 Oct 2014 17:16:57 +0100

> On Tue, Oct 28, 2014 at 10:25:41PM +0800, Fengguang Wu wrote:
>> [ 122.247299] ------------[ cut here ]------------
>> [ 122.247328] WARNING: CPU: 0 PID: 61 at kernel/sched/core.c:7312 __might_sleep+0x50/0x249()
>> [ 122.247334] do not call blocking ops when !TASK_RUNNING; state=2 set at [<c106ffd9>] prepare_to_wait+0x3c/0x5f
>> [ 122.247339] Modules linked in:
>> [ 122.247349] CPU: 0 PID: 61 Comm: kworker/u2:1 Not tainted 3.18.0-rc2-00037-g24574709 #136
>> [ 122.247350] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
>> [ 122.247368] Workqueue: netns cleanup_net
>> [ 122.247377] c1071d83 d2b83dd8 d2b83dac c15887b1 d2b83dc8 c104c4c6 00001c90 c1068ebf
>> [ 122.247383] 00000000 c17b67e3 0000026d d2b83de0 c104c508 00000009 d2b83dd8 c17b5d4b
>> [ 122.247388] d2b83df4 d2b83e0c c1068ebf c17b5cec 00001c90 c17b5d4b 00000002 c106ffd9
>> [ 122.247389] Call Trace:
>> [ 122.247393] [<c1071d83>] ? down_trylock+0x23/0x2c
>> [ 122.247402] [<c15887b1>] dump_stack+0x16/0x18
>> [ 122.247413] [<c104c4c6>] warn_slowpath_common+0x66/0x7d
>> [ 122.247416] [<c1068ebf>] ? __might_sleep+0x50/0x249
>> [ 122.247419] [<c104c508>] warn_slowpath_fmt+0x2b/0x2f
>> [ 122.247422] [<c1068ebf>] __might_sleep+0x50/0x249
>> [ 122.247424] [<c106ffd9>] ? prepare_to_wait+0x3c/0x5f
>> [ 122.247426] [<c106ffd9>] ? prepare_to_wait+0x3c/0x5f
>> [ 122.247432] [<c158c364>] mutex_lock_nested+0x23/0x347
>> [ 122.247436] [<c1075105>] ? trace_hardirqs_on+0xb/0xd
>> [ 122.247439] [<c158eb0c>] ? _raw_spin_unlock_irqrestore+0x66/0x78
>> [ 122.247445] [<c1570e10>] rtnl_lock+0x14/0x16
>> [ 122.247449] [<c156516b>] default_device_exit_batch+0x54/0xf3
>> [ 122.247452] [<c1570e1f>] ? rtnl_unlock+0xd/0xf
>> [ 122.247454] [<c1070233>] ? __wake_up_sync+0x12/0x12
>> [ 122.247461] [<c155e35d>] ops_exit_list+0x20/0x40
>> [ 122.247464] [<c155ec96>] cleanup_net+0xbe/0x140
>> [ 122.247473] [<c105ffe4>] process_one_work+0x29e/0x643
>> [ 122.247479] [<c1061215>] worker_thread+0x23a/0x311
>> [ 122.247482] [<c1060fdb>] ? rescuer_thread+0x204/0x204
>> [ 122.247486] [<c10648cc>] kthread+0xbe/0xc3
>> [ 122.247490] [<c158f4c0>] ret_from_kernel_thread+0x20/0x30
>> [ 122.247492] [<c106480e>] ? kthread_stop+0x364/0x364
>> [ 122.247495] ---[ end trace 2073c37ae3c8b3b4 ]---
>
> Ah, more of that. Thanks!
>
> Dave, this relies on bits currently in tip/sched/core, if you're ok I'll
> merge it through that tree.

Yep, no problem:

Acked-by: David S. Miller <davem@xxxxxxxxxxxxx>
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