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Message-ID: <46406656.9060504@gmail.com>
Date: Tue, 08 May 2007 14:00:22 +0200
From: Jiri Slaby <jirislaby@gmail.com>
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To: Jiri Slaby <jirislaby@gmail.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>, Andrew Morton <akpm@linux-foundation.org>,
       "Rafael J. Wysocki" <rjw@sisk.pl>, Pavel Machek <pavel@ucw.cz>,
       <linux-pm@lists.linux-foundation.org>,
       Linux kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: 2.6.21-mm1 hwsusp: BUG at workqueue.c:106
References: <46403B7F.1050009@gmail.com> <20070508021131.438cee31.akpm@linux-foundation.org> <20070508105528.GA86@tv-sign.ru> <46405A67.8020105@gmail.com>
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Jiri Slaby napsal(a):
> Oleg Nesterov napsal(a):
>> On 05/08, Andrew Morton wrote:
>>> On Tue, 08 May 2007 10:57:35 +0200 Jiri Slaby <jirislaby@gmail.com> wrote:
>>>
>>>> this occured in dmesg during resuming from hwsusp in 2.6.21-mm1 (captured
>>>> through netconsole). Perfectly reproducible, it simply happens each time I
>>>> try it.
>>> Let's cc Oleg.
>>>
>>>> usb_endpoint usbdev5.1_ep00: PM: resume from 0, parent usb5 still 2
>>>> ------------[ cut here ]------------
>>>> kernel BUG at /home/l/latest/xxx/kernel/workqueue.c:106!
>>>> invalid opcode: 0000 [#1]
>>>> SMP
>>>> Modules linked in: ipv6 floppy ohci1394 ieee1394 parport_pc parport usbhid
>>>> ehci_hcd pata_acpi ff_memless sr_mod cdrom
>>>> CPU:    1
>>>> EIP:    0060:[<c0132161>]    Not tainted VLI
>>>> EFLAGS: 00010046   (2.6.21-mm1 #272)
>>>> EIP is at insert_work+0x6d/0x71
>>>> eax: c1c3b3c0   ebx: c1814aa0   ecx: 00000001   edx: c1814aa0
>>>> esi: c1c3b340   edi: 00000282   ebp: c04d2f68   esp: c04d2f50
>>>> ds: 007b   es: 007b   fs: 00d8  gs: 0000  ss: 0068
>>>> Process swapper (pid: 0, ti=c04d2000 task=c1c26030 task.ti=c1c20000)
>>>> Stack: c4685f54 c18148ac c04d2f98 c013816f c1c3b340 c1814aa0 c04d2f88 c013256c
>>>>        00000066 c1814880 c1c5e000 c04d2fc4 c01325a1
>>>> c1c5e000 00000100 c012ba35 00000000 c04d2fb8 c01333f4 Call Trace:
>>>>  [<c0104f27>]  [<c0104fe2>] show_stack_log_lvl+0xa5/0xca
>>>> show_registers+0x1e2/0x2da
>>>>  [<c01053f5>]  [<c010559a>] do_trap+0x84/0xaa
>>>> do_invalid_op+0x88/0x92
>>>>  [<c0378662>]  [<c013256c>] __queue_work+0x22/0x33
>>>> delayed_work_timer_fn+0x24/0x2a
>>>>  [<c012ba35>]  [<c01288a9>] __do_softirq+0x75/0xe6
>>>> do_softirq+0x63/0xac
>>>>  [<c0128713>]  [<c0116d7e>] smp_apic_timer_interrupt+0x5c/0x88
>>>> apic_timer_interrupt+0x28/0x30
[...]
>> queue_delayed_work().
>>
>> Probably, cancel_delayed_work(&delayed_work->work) was called with the ->timer
>> pending. This is wrong, cancel_delayed_work() clears _PENDING unconditionally,
>> that is why the comment says
>>
>> 	it is expected that, prior to calling cancel_work_sync(), the caller has
>> 	arranged for the work to not be requeued.
>>
>> (Just in case, after make-cancel_rearming_delayed_work-reliable.patch this is still
>>  wrong (as documented) to do cancel_delayed_work() before cancel_delayed_timer(),
>>  but should work correctly).
[...]
>> --- OLD/kernel/workqueue.c~	2007-05-06 00:01:06.000000000 +0400
>> +++ OLD/kernel/workqueue.c	2007-05-08 14:50:39.000000000 +0400
>> @@ -103,7 +103,10 @@ static inline void set_wq_data(struct wo
>>  {
>>  	unsigned long new;
>>  
>> -	BUG_ON(!work_pending(work));
>> +	if (!work_pending(work)) {
>> +		printk(KERN_ERR "BUG: set_wq_data ");
>> +		print_symbol("%s\n", (unsigned long) work->func);
>> +	}
>>  
>>  	new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING);
>>  	new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work);

vmstat_update+0x0/0x2b

Ccing Christoph.

regards,
-- 
http://www.fi.muni.cz/~xslaby/            Jiri Slaby
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
B674 9967 0407 CE62 ACC8  22A0 32CC 55C3 39D4 7A7E
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