Re: Commit 7eaceaccab5f40 causing boot hang.
From: Jens Axboe
Date: Tue Mar 29 2011 - 09:59:49 EST
On 2011-03-29 10:52, Rob Landley wrote:
> On 03/29/2011 01:35 AM, Jens Axboe wrote:
>> On 2011-03-29 08:19, Rob Landley wrote:
>>> Using the attached config (run through oldconfig and holding down
>>> enter), 2.6.38 boots but current -git hangs. I've bisected it to this
>>> commit:
>>>
>>> 7eaceaccab5f40bbfda044629a6298616aeaed50 is the first bad commit
>>> commit 7eaceaccab5f40bbfda044629a6298616aeaed50
>>> Author: Jens Axboe <jaxboe@xxxxxxxxxxxx>
>>> Date: Thu Mar 10 08:52:07 2011 +0100
>>>
>>> block: remove per-queue plugging
>>>
>>> Code has been converted over to the new explicit on-stack plugging,
>>> and delay users have been converted to use the new API for that.
>>> So lets kill off the old plugging along with aops->sync_page().
>>>
>>> Signed-off-by: Jens Axboe <jaxboe@xxxxxxxxxxxx>
>>>
>>> I suspect it broke CONFIG_IDE_GD_ATA. (The symptoms change a bit in
>>> later versions, when that was first introduced it hung right after
>>> discovering hda, now it makes it to freeing kernel memory and then hangs
>>> trying to launch init. But "the disk hangs a lot" still seems to
>>> describe the problem.)
>>
>> That is the case even with 9ced0b95b3993660e7990cf6bf68c1a80f31544e,
>> which was otherwise supposed to fix this queue stall?
>>
>
> The first time I tried it, that version did manage to launch init, and
> then hung two lines later with ".udev/ already exists on the static
> /dev! ..." and the cursor still on the end of that line. Could be an
> unrelated bug, hard to tell.
>
> I tried it three more times and it hung right after "freeing unused
> kernel memory", with no output from init. (I also tried adding
> "init=/bin/bash" to the kernel command line and it still hung after the
> "freeing unused kernel memory" line, with no output from bash. Pressed
> a lot of keys, nothing echoed back.)
>
> This is an improvement over hanging earlier in the boot, but userspace
> isn't really happy at the moment.
>
> 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)
--
Jens Axboe
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