Kernel oops in i915 on 5.4.0-18-generic

[Sultan Alsawaf]

I was running 5.4.0-18-generic and got the following splat doing nothing interesting in particular:
BUG: unable to handle page fault for address: ffffffff84abf450
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 4d420e067 P4D 4d420e067 PUD 4d420f063 PMD 0
Oops: 0010 [#1] SMP
CPU: 11 PID: 1114 Comm: kworker/11:3 Tainted: P U O 5.4.0-18-generic #22
Hardware name: Dell Inc. Precision 5540/0FMYX6, BIOS 1.5.0 12/25/2019
Workqueue: events __intel_wakeref_put_work [i915]
RIP: 0010:0xffffffff84abf450
Code: Bad RIP value.
RSP: 0018:ffffad7380757cc0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff89ebc46a6d98 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff89ebc46a6d98
RBP: ffffad7380757d40 R08: ffff89ebd88eeb58 R09: ffff89ebd88eec28
R10: 0000000000000000 R11: ffffffffac065868 R12: ffff89ebc46a6d98
R13: 0000000000000000 R14: 0000000000000001 R15: ffff89ebd00283c0
FS: 0000000000000000(0000) GS:ffff89ebdc2c0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff84abf426 CR3: 00000004d420a002 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ? __flush_work+0x51/0x1d0
 ? wake_up_process+0x15/0x20
 __cancel_work_timer+0x10e/0x190
 ? _cond_resched+0x19/0x30
 ? synchronize_irq+0x3e/0xb0
 cancel_work_sync+0x10/0x20
 gen6_disable_rps_interrupts+0xa0/0xd0 [i915]
 gen6_rps_idle+0x1f/0xf0 [i915]
 __gt_park+0x93/0xa0 [i915]
 ____intel_wakeref_put_last+0x1f/0x50 [i915]
 __intel_wakeref_put_work+0x37/0x40 [i915]
 process_one_work+0x1eb/0x3b0
 worker_thread+0x4d/0x400
 kthread+0x104/0x140
 ? process_one_work+0x3b0/0x3b0
 ? kthread_park+0x90/0x90
 ret_from_fork+0x1f/0x40

I looked through the differences between 5.4.0-18 and the tip of master-next for focal ("UBUNTU: upstream stable to v5.4.29"), and there are no new changes to i915 that could've fixed this.

I've filed a bug with Intel, since this doesn't seem to be Ubuntu-specific: https://gitlab.freedesktop.org/drm/intel/issues/1597

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1870242

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Colin Ian King (colin-king)]

Looks like the work queue function for i915 driver is borked and is jumping to the wrong address.