Re: [xen_netfront] - Xen PVH VM: kernel upgrade 6.9.10 > 6.10.7 results in crash

[Jan Beulich <jbeulich@xxxxxxxx>]

On 02.09.2024 10:32, Arthur Borsboom wrote:
> On Mon, 2 Sept 2024 at 10:27, Jan Beulich <jbeulich@xxxxxxxx> wrote:
> 
>> On 01.09.2024 10:54, Arthur Borsboom wrote:
>>> After upgrading kernel 6.9.10 to 6.10.7 all Xen PVH VM's became
>> unavailable.
>>> Downgrading the kernel back to 6.9.10 makes the VM's work again.
>>
>> I don't think I can help with the crash, but: How did you conclude it's
>> xen-netfront? The data you provide ...
>>
>>> Snippet stack trace + kernel logs (good and bad) attached.
>>>
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: xen_netfront: Initialising
>> Xen
>>> virtual ethernet driver
>>> Sep 01 08:59:21 web3.aramgroup.com systemd-udevd[248]: vfb-0: Worker
>> [250]
>>> terminated by signal 9 (KILL).
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: BUG: kernel NULL pointer
>>> dereference, address: 0000000000000060
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: #PF: supervisor read access
>> in
>>> kernel mode
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: #PF: error_code(0x0000) -
>>> not-present page
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: PGD 0 P4D 0
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: Oops: Oops: 0000 [#1] PREEMPT
>>> SMP PTI
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: CPU: 0 PID: 250 Comm:
>>> (udev-worker) Not tainted 6.10.7-arch1-1 #1
>>> 2b2df360fbb0436393dc89f6589e9eeea2964ecb
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: RIP:
>>> 0010:video_is_primary_device+0x9/0x40
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: Code: 48 89 d8 5b c3 cc cc
>> cc cc
>>> 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
>> f3
>>> 0f 1e fa 0f 1f 44 00 00 <48> 81 7f 60 80 e3 54 90 74 07 31 c0 c3 cc cc cc
>>> cc 53 48 89 fb 48
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: RSP: 0000:ffffbb06808d7a60
>>> EFLAGS: 00010246
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: RAX: 0000000000000000 RBX:
>>> ffff90ca41367800 RCX: 0000000000000000
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: RDX: 0000000000000000 RSI:
>>> 0000000000000246 RDI: 0000000000000000
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: RBP: 0000000000000000 R08:
>>> 0000000000000060 R09: 0000000000000000
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: R10: ffffbb06808d7a78 R11:
>>> 0000000000000006 R12: ffffbb06808d7a90
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: R13: ffff90ca41367a88 R14:
>>> ffff90ca41367a60 R15: ffff90cb41330788
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: FS:  000072bfd74c0880(0000)
>>> GS:ffff90ce33a00000(0000) knlGS:0000000000000000
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: CS:  0010 DS: 0000 ES: 0000
>> CR0:
>>> 0000000080050033
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: CR2: 0000000000000060 CR3:
>>> 0000000001326002 CR4: 00000000003706f0
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: DR0: 0000000000000000 DR1:
>>> 0000000000000000 DR2: 0000000000000000
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: DR3: 0000000000000000 DR6:
>>> 00000000fffe0ff0 DR7: 0000000000000400
>>> Sep 01 08:59:21 web3.aramgroup.com kernel: Call Trace:
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:  <TASK>
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:  ? __die_body.cold+0x19/0x27
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:  ?
>> page_fault_oops+0x15a/0x2d0
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:  ?
>> __kernfs_new_node+0x17d/0x200
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:  ? exc_page_fault+0x81/0x190
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:  ?
>> asm_exc_page_fault+0x26/0x30
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:  ?
>>> video_is_primary_device+0x9/0x40
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:  do_fb_registered+0x100/0x110
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:
>> fbcon_fb_registered+0x4d/0x70
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:
>> register_framebuffer+0x198/0x2a0
>>> Sep 01 08:59:21 web3.aramgroup.com kernel:  xenfb_probe+0x30d/0x430
>>> [xen_fbfront 61323dae510a72b3d2c332a2b0273cf6365e9002]
>>
>> ... clearly points at xen-fbfront. And surely the people to help with that
>> is not the same set as those to help with a networking issue.
> 
> My interpretation of the stack trace is wrong.
> 
> How can I get this to the right people?
> Shall I send another mail with [xen-fbfront] in the subject?

This may help. You may also be lucky to catch the attention without re-sending.
I can't really suggest which one's better; it's likely all up to you.

Jan