Re: Commit 7eaceaccab5f40 causing boot hang.

From: Jens Axboe
Date: Thu Mar 31 2011 - 06:07:15 EST


On 2011-03-31 11:11, Rob Landley wrote:
> On 03/31/2011 04:02 AM, Jens Axboe wrote:
>> On 2011-03-30 15:52, Rob Landley wrote:
>>> On 03/30/2011 06:38 AM, Jens Axboe wrote:
>>>> On 2011-03-30 08:06, Rob Landley wrote:
>>>>> On 03/29/2011 10:51 AM, Pete Clements wrote:
>>>>>> Quoting Jens Axboe
>>>>>> >
>>>>>> > On 2011-03-29 16:13, Rob Landley wrote:
>>>>>> > > On 03/29/2011 08:59 AM, Jens Axboe wrote:
>>>>>> > >> On 2011-03-29 10:52, Rob Landley wrote:
>>>>>> > >>> I'm booting all this under kvm or qemu, by the way:
>>>>>> > >>>
>>>>>> > >>> qemu-system-x86_64 -m 1024 -kernel arch/x86/boot/bzImage \
>>>>>> > >>> -hda ~/sid.ext3 -append "root=/dev/hda rw"
>>>>>> > >>>
>>>>>> > >>> Sometimes with init=/bin/bash in that last quoted bit. The root
>>>>>> > >>> filesystem's debian sid but that's probably not relevant because it
>>>>>> > >>> worked fine with .38.
>>>>>> > >>
>>>>>> > >> Does this help?
>>>>>> > >>
>>>>>> > >> diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
>>>>>> > >> index 0e406d73..ca27d30 100644
>>>>>> > >> --- a/drivers/ide/ide-io.c
>>>>>> > >> +++ b/drivers/ide/ide-io.c
>>>>>> > >> @@ -570,8 +570,7 @@ void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
>>>>>> > >> spin_unlock_irqrestore(q->queue_lock, flags);
>>>>>> > >>
>>>>>> > >> /* Use 3ms as that was the old plug delay */
>>>>>> > >> - if (rq)
>>>>>> > >> - blk_delay_queue(q, 3);
>>>>>> > >> + blk_delay_queue(q, 3);
>>>>>> > >> }
>>>>>> > >>
>>>>>> > >> static int drive_is_ready(ide_drive_t *drive)
>>>>>> > >>
>>>>>> > >
>>>>>> > > Nope, still hung the same way.
>>>>>> >
>>>>>> > Funky. I'll try and reproduce this tonight.
>>>>>> >
>>>>>> > --
>>>>>> > Jens Axboe
>>>>>> >
>>>>>>
>>>>>> I have had a similiar problem (reported earlier) unable to boot.
>>>>>> With git15-18 hung with IDE drives (hda), git19-21 moved the hang down to
>>>>>> the IDE CDROM (hdc). Applied the above patch and now booted into git21 without
>>>>>> any hang and all appears ok.
>>>>>
>>>>> It may have made it better for me, it's hard to tell.
>>>>>
>>>>> I did a fresh pull, re-applied the patch, and tried again with
>>>>> init=/bin/sh and it booted to the shell prompt... which then hung when I
>>>>> did "ls -l /".
>>>>>
>>>>> If I let it boot normally, init announces itself, gives a spurious
>>>>> warning about a fstab field (which it's been doing for a while, my fault
>>>>> but harmless), then hangs.
>>>>>
>>>>>> This is i386, UP.
>>>>>
>>>>> I'm doing x86-64 SMP.
>>>>
>>>> I think we have the same issue the other location. How about this, then:
>>>>
>>>> diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
>>>> index 0e406d73..4978ec3 100644
>>>> --- a/drivers/ide/ide-io.c
>>>> +++ b/drivers/ide/ide-io.c
>>>> @@ -549,12 +549,11 @@ plug_device:
>>>> spin_unlock_irq(&hwif->lock);
>>>> ide_unlock_host(host);
>>>> plug_device_2:
>>>> + blk_delay_queue(q, queue_run_ms);
>>>> spin_lock_irq(q->queue_lock);
>>>>
>>>> - if (rq) {
>>>> + if (rq)
>>>> blk_requeue_request(q, rq);
>>>> - blk_delay_queue(q, queue_run_ms);
>>>> - }
>>>> }
>>>>
>>>> void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
>>>> @@ -570,8 +569,7 @@ void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
>>>> spin_unlock_irqrestore(q->queue_lock, flags);
>>>>
>>>> /* Use 3ms as that was the old plug delay */
>>>> - if (rq)
>>>> - blk_delay_queue(q, 3);
>>>> + blk_delay_queue(q, 3);
>>>> }
>>>>
>>>> static int drive_is_ready(ide_drive_t *drive)
>>>>
>>>
>>> Did a fresh pull and applied that patch. (It conflicts with your
>>> previous one, but looks like it includes it.)
>>>
>>> Now it hangs after the "EXT3-fs: barriers not enabled" line, doesn't
>>> make it to init.
>>
>> I have tried hard to reproduce this, but even stock 2.6.39-rc1 works
>> fine for me here. Setup a KVM image with a debian 6 install, then
>> converted it to IDE and booting it with a custom kernel like you are.
>> Works fine, boots and I can do disk activity tests and it all works.
>>
>> Can you send me your .config?
>
> It was attached to the first message in this series, here it is again.
>
> I update it via "make oldconfig" and hold down return.
>
> I boot it via:
>
> qemu-system-x86_64 -m 1024 -kernel arch/x86/boot/bzImage \
> -hda ~/sid.ext3 -append "root=/dev/hda rw"

Much better, I see the hang now! Now to try and diagnose...

--
Jens Axboe

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