Re: [Xen-devel] kernel BUG at drivers/xen/blkback/blkback-pagemap.c:65!

[jake wires <jake.wires@xxxxxxxxx>]

the attached patch fixes one possible code path to the failed assertion, but it's not clear from the stack trace that this path was actually taken.  were there any interesting errors in the dom0 logs?

Signed-off-by: Jake Wires <jake.wires@xxxxxxxxxx>

On Thu, Jul 16, 2009 at 10:01 AM, Keir Fraser <keir.fraser@xxxxxxxxxxxxx> wrote:

I suggest you stick with the xen-3.4.0 tag in linux-2.6.18-xen.hg and see if
that serves you better. This particular bug may have been introduced by the
blktap2 additions (at least the BUG() is in a file which that patch
introduces). Cc'ed the blktap2 guys.

 -- Keir

On 16/07/2009 17:19, "Christopher S. Aker" <caker@xxxxxxxxxxxx> wrote:

> Xen 3.3-testing @ changeset 18651, 64bit
> dom0 2.6.18.8 @ changeset 888, PAE
>
> Files: http://theshore.net/~caker/xen/BUGS/1.22/
>
> clearing empty pagemap 311
> ------------[ cut here ]------------
> kernel BUG at drivers/xen/blkback/blkback-pagemap.c:65!
> invalid opcode: 0000 [#1]
> SMP
> Modules linked in: e1000e e1000
> CPU:    0
> EIP:    0061:[<c0390507>]    Not tainted VLI
> EFLAGS: 00010292   (2.6.18.8-888-1 #1)
> EIP is at blkback_pagemap_clear+0x57/0xa0
> eax: 0000001e   ebx: 00000137   ecx: 00000000   edx: fdb4e000
> esi: d24f4ea0   edi: c0691a14   ebp: d24f4e94   esp: cdc0fbd4
> ds: 007b   es: 007b   ss: 0069
> Process blkback.166.xvd (pid: 30401, ti=cdc0e000 task=cb028570
> task.ti=cdc0e000)
> Stack: c05441a0 00000137 00000003 d23463f0 00000002 0000023e c038e00d
> cdc0fbf8
>         00000135 d2b65000 00000000 00000000 00000000 00000010 00000000
> d2b66000
>         00000000 00000000 00000000 0000037b 00003b18 00005617 00000000
> 00000000
> Call Trace:
>   [<c038e00d>] fast_flush_area+0xad/0x130
>   [<c0439774>] dm_request+0xc4/0xf0
>   [<c02eda83>] generic_make_request+0x173/0x210
>   [<c03841ca>] evtchn_do_upcall+0x10a/0x200
>   [<c02edb89>] submit_bio+0x69/0x120
>   [<c0174217>] bio_add_page+0x37/0x50
>   [<c038e58d>] dispatch_rw_block_io+0x1fd/0x730
>   [<c04fcd4c>] schedule+0x33c/0xa00
>   [<c02ea84a>] elv_next_request+0x12a/0x220
>   [<c02ef133>] __generic_unplug_device+0x33/0x40
>   [<c02ef5e5>] generic_unplug_device+0x15/0x50
>   [<c043a07a>] dm_table_unplug_all+0x2a/0x40
>   [<c038eb73>] blkif_schedule+0xb3/0x620
>   [<c04fcd4c>] schedule+0x33c/0xa00
>   [<c038eac0>] blkif_schedule+0x0/0x620
>   [<c0136b62>] kthread+0xc2/0x100
>   [<c0136aa0>] kthread+0x0/0x100
>   [<c0102c45>] kernel_thread_helper+0x5/0x10
> Code: 1a 69 c0 7d 4d 8d 04 5b bf 08 1a 69 c0 8d 2c 82 b9 0c 00 00 00 89
> ee f3 a6 75 18 89 5c 24 04 c7 04 24 a0 41 54 c0 e8 f9 13 d9 ff <0f> 0b
> 41 00 50 65 55 c0 b9 03 00 00 00 89 ef 31 c0 f3 ab 8b 5c
> EIP: [<c0390507>] blkback_pagemap_clear+0x57/0xa0 SS:ESP 0069:cdc0fbd4
>
> -Chris
>
>
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