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Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value |
Date: |
Mon, 13 Jun 2016 12:56:46 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 06/13/2016 11:43 AM, Cédric Le Goater wrote:
> On 06/13/2016 06:47 PM, Eric Blake wrote:
>> On 06/13/2016 10:25 AM, Cédric Le Goater wrote:
>>
>>>
>>> It seems that commit 243e6f69c129 ("m25p80: Switch to byte-based block
>>> access")
>>> is bringing another issue :
>>>
>>> qemu-system-arm:
>>> /home/legoater/work/qemu/qemu-ast2400-mainline.git/block/io.c:1252:
>>> bdrv_aligned_pwritev: Assertion `!qiov || bytes == qiov->size' failed.
>>> Aborted (core dumped)
>>
>> Can you provide a more complete stack dump,
>
> yes, see below.
>
>> and/or a recipe on how to repeat the assertion?
>
> That's more difficult right now. The patchset I am working on is not
> mainline. It adds the SPI controller to the ast2400 soc and it uses
> m25p80 flash modules with -mtdblock.
>
> I am trying to rebase on qemu's head to send it and I am hitting this
> issue. So I need to find a simpler way to reproduce, with code only in
> mainline of course.
>
> Until then, here is a gdb backtrace. Sorry about that.
>
> #4 0x00007fa81c6694ac in bdrv_aligned_pwritev (bs=0x7fa81d4dd050,
> req=<optimized out>, offset=30878208,
> bytes=512, qiov=0x7fa7f47fee60, flags=0)
> at /home/legoater/work/qemu/qemu-ast2400-mainline.git/block/io.c:1243
> #5 0x00007fa81c669ecb in bdrv_co_pwritev (bs=0x7fa81d4dd050, offset=8,
> bytes=512, qiov=0x7fa80d5191c0,
> flags=(BDRV_REQ_COPY_ON_READ | BDRV_REQ_ZERO_WRITE | BDRV_REQ_MAY_UNMAP |
> BDRV_REQ_NO_SERIALISING | BDRV_REQ_FUA | unknown: 4278124256),
> address@hidden(unknown: 0))
> at /home/legoater/work/qemu/qemu-ast2400-mainline.git/block/io.c:1492
That 'flags' value looks bogus...
> #6 0x00007fa81c65e367 in blk_co_pwritev (blk=0x7fa81d4c5b60,
> offset=30878208, bytes=256, qiov=0x7fa80d5191c0,
> flags=(unknown: 0)) at
> /home/legoater/work/qemu/qemu-ast2400-mainline.git/block/block-backend.c:788
> #7 0x00007fa81c65e49b in blk_aio_write_entry (opaque=0x7fa7e849aca0)
> at
> /home/legoater/work/qemu/qemu-ast2400-mainline.git/block/block-backend.c:977
> #8 0x00007fa81c6c823a in coroutine_trampoline (i0=<optimized out>,
> i1=<optimized out>)
> at
> /home/legoater/work/qemu/qemu-ast2400-mainline.git/util/coroutine-ucontext.c:78
> #9 0x00007fa818ea8f00 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
and we don't get anything further in the backtrace beyond coroutines, to
see who's sending the bad parameters. I recently debugged a bogus flags
in bdrv_aio_preadv, by hoisting an assert to occur before coroutines are
used in blk_aio_prwv():
https://lists.gnu.org/archive/html/qemu-devel/2016-06/msg02948.html
I've just posted v2 of that patch (now a 2/2 series), but in v2 no
longer kept the assert at that point. But maybe the correct fix, and/or
the hack for catching the bug prior to coroutines, will help you debug
where the bad arguments are coming from.
> #10 0x00007fa80d5189d0 in ?? ()
> #11 0x0000000000000000 in ?? ()
> (gdb) up 4
> #4 0x00007fa81c6694ac in bdrv_aligned_pwritev (bs=0x7fa81d4dd050,
> req=<optimized out>, offset=30878208,
> bytes=512, qiov=0x7fa7f47fee60, flags=0)
> at /home/legoater/work/qemu/qemu-ast2400-mainline.git/block/io.c:1243
> 1243 assert(!qiov || bytes == qiov->size);
> (gdb) p *qiov
> $1 = {iov = 0x7fa81da671d0, niov = 1, nalloc = 1, size = 256}
>
>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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- Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value, Cédric Le Goater, 2016/06/13
- Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value, Eric Blake, 2016/06/13
- Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value, Cédric Le Goater, 2016/06/13
- Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value,
Eric Blake <=
- Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value, Cédric Le Goater, 2016/06/14
- Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value, Kevin Wolf, 2016/06/14
- Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value, Cédric Le Goater, 2016/06/14
- Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value, Kevin Wolf, 2016/06/15
- Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value, Cédric Le Goater, 2016/06/15
Re: [Qemu-devel] [PATCH] m25p80: fix test on blk_pread() return value, Cédric Le Goater, 2016/06/15