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

[Jan Beulich <jbeulich@xxxxxxxx>]

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.

Jan