9p: BUG: unable to handle kernel paging request at ffff880035698000

9p: BUG: unable to handle kernel paging request at ffff880035698000

[Sasha Levin]

Hi,

I was using the KVM tool for tests with trinity on top of a virtio-9p filesystem, and started seeing the BUGs below when I've put some pressure on the 9p fs (not much, just started writing the logs from trinity to a 9p fs).

This reproduces not so easily, but it happens 2-3 times a day.

[  156.384520] BUG: unable to handle kernel paging request at ffff880035698000
[  156.386845] IP: [<ffffffff825be143>] p9_release_pages+0x43/0x60
[  156.388766] PGD 321d063 PUD 3221063 PMD 1ffa9067 PTE 35698160
[  156.388766] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[  156.393871] CPU 0
[  156.393871] Pid: 10293, comm: trinity Not tainted 3.3.0-rc4-next-20120220-sasha-00003-g949d91b #14
[  156.400127] RIP: 0010:[<ffffffff825be143>]  [<ffffffff825be143>] p9_release_pages+0x43/0x60
[  156.402161] RSP: 0018:ffff8800356edbf8  EFLAGS: 00010202
[  156.402161] RAX: 0000000000000001 RBX: ffff880035697ff8 RCX: 0000000000000000
[  156.402161] RDX: ffff8800330cb000 RSI: 0000000000000001 RDI: ffffea0000cfed40
[  156.402161] RBP: ffff8800356edc18 R08: 0000000000000001 R09: 0000000000000000
[  156.402161] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[  156.407866] R13: 0000000000000001 R14: ffff880038a58070 R15: 0000000000000000
[  156.407866] FS:  00007fb4bf398700(0000) GS:ffff88003de00000(0000) knlGS:0000000000000000
[  156.407866] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  156.410381] CR2: ffff880035698000 CR3: 00000000355b2000 CR4: 00000000000406f0
[  156.410949] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  156.410949] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  156.413619] Process trinity (pid: 10293, threadinfo ffff8800356ec000, task ffff8800330cb000)
[  156.415369] Stack:
[  156.415369]  ffff8800356edc98 ffff8800356edc98 0000000000000000 ffff8800356edc98
[  156.417242]  ffff8800356edcf8 ffffffff825bed35 0000000000000076 0000000000000017
[  156.417242]  ffff8800356edcb0 ffff8800330cb000 0000000000001000 0000000000000286
[  156.417242] Call Trace:
[  156.417242]  [<ffffffff825bed35>] p9_virtio_zc_request+0xd5/0x510
[  156.417242]  [<ffffffff810d3a10>] ? wake_up_bit+0x40/0x40
[  156.417242]  [<ffffffff825ba548>] p9_client_zc_rpc+0xe8/0x4f0
[  156.417242]  [<ffffffff810e9155>] ? sched_clock_local+0x25/0x90
[  156.417242]  [<ffffffff810df381>] ? get_parent_ip+0x11/0x50
[  156.424263]  [<ffffffff810df381>] ? get_parent_ip+0x11/0x50
[  156.424263]  [<ffffffff825babf2>] p9_client_write+0xe2/0x1e0
[  156.424263]  [<ffffffff81592e15>] v9fs_file_write_internal+0x65/0x140
[  156.424263]  [<ffffffff81592f7c>] v9fs_file_write+0x8c/0xb0
[  156.424263]  [<ffffffff811d6258>] vfs_write+0xc8/0x190
[  156.424263]  [<ffffffff811d640f>] sys_write+0x4f/0x90
[  156.424263]  [<ffffffff82663f39>] system_call_fastpath+0x16/0x1b
[  156.424263] Code: ff 74 31 85 f6 74 2d 45 31 e4 eb 0e 0f 1f 40 00 45 39 e5 0f 1f 44 00 00 74 1a 66 0f 1f 44 00 00 e8 53 ef bb fe$
[  156.432262] RIP  [<ffffffff825be143>] p9_release_pages+0x43/0x60
[  156.432262]  RSP <ffff8800356edbf8>
[  156.434735] CR2: ffff880035698000

Re: [V9fs-developer] 9p: BUG: unable to handle kernel paging request at ffff880035698000

[M. Mohan Kumar]

On 02/21/2012 09:53 PM, Sasha Levin wrote:
> Hi,
>
> I was using the KVM tool for tests with trinity on top of a virtio-9p filesystem, and started seeing the BUGs below when I've put some pressure on the 9p fs (not much, just started writing the logs from trinity to a 9p fs).
Hi Sasha,

You mentioned about testing with trinity, Where can I find this trinity 
? Is is some test suite ? Were you running 9p as root?

Which kernel version you were using? Is this bug still reproducible?

Re: [V9fs-developer] 9p: BUG: unable to handle kernel paging request at ffff880035698000

[Dave Jones]

On Wed, Mar 14, 2012 at 11:05:42AM +0530, M. Mohan Kumar wrote:
 > On 02/21/2012 09:53 PM, Sasha Levin wrote:
 > > Hi,
 > >
 > > I was using the KVM tool for tests with trinity on top of a virtio-9p filesystem, and started seeing the BUGs below when I've put some pressure on the 9p fs (not much, just started writing the logs from trinity to a 9p fs).
 > Hi Sasha,
 > 
 > You mentioned about testing with trinity, Where can I find this trinity 
 > ? Is is some test suite ?

git://git.codemonkey.org.uk/trinity

	Dave

Re: [V9fs-developer] 9p: BUG: unable to handle kernel paging request at ffff880035698000

[Sasha Levin]

On Wed, Mar 14, 2012 at 7:35 AM, M. Mohan Kumar <mohan@in.ibm.com> wrote:
> On 02/21/2012 09:53 PM, Sasha Levin wrote:
>>
>> Hi,
>>
>> I was using the KVM tool for tests with trinity on top of a virtio-9p
>> filesystem, and started seeing the BUGs below when I've put some pressure on
>> the 9p fs (not much, just started writing the logs from trinity to a 9p fs).
>
> Hi Sasha,
>
> You mentioned about testing with trinity, Where can I find this trinity ? Is
> is some test suite ? Were you running 9p as root?

I was using the fuzzer linked by davej in the previous mail.

9p was the root partition, and there was another 9p partition mounted
on top of that root 9p.

> Which kernel version you were using? Is this bug still reproducible?

It was running the linux-next kernel of the day I sent the mail, I
don't see it happening any more - but it could be because a lot of new
kernel bugs showed up and they happen before this 9p issue happens.

Re: [V9fs-developer] 9p: BUG: unable to handle kernel paging request at ffff880035698000

[M. Mohan Kumar]

Thanks Dave & Sasha, I will try with trinity and update.

On Wed, 14 Mar 2012 10:23:01 -0400, Dave Jones <davej@redhat.com> wrote:
> On Wed, Mar 14, 2012 at 11:05:42AM +0530, M. Mohan Kumar wrote:
>  > On 02/21/2012 09:53 PM, Sasha Levin wrote:
>  > > Hi,
>  > >
>  > > I was using the KVM tool for tests with trinity on top of a virtio-9p filesystem, and started seeing the BUGs below when I've put some pressure on the 9p fs (not much, just started writing the logs from trinity to a 9p fs).
>  > Hi Sasha,
>  > 
>  > You mentioned about testing with trinity, Where can I find this trinity 
>  > ? Is is some test suite ?
> 
> git://git.codemonkey.org.uk/trinity
> 
> 	Dave
>