Comment 30 for bug 2068738

How do we fix this?

On Tue, Jun 18, 2024 at 9:40 AM Acru <email address hidden> wrote:

> Hey,
> After disabling the kernel update via the update manager, it now got
> installed again, again resulting in a not working system.
> Isn't it possible to just completely remove this one version from the repo?
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/2068738
>
> Title:
> AMD GPUs fail with null pointer dereference when IOMMU enabled,
> leading to black screen
>
> Status in linux package in Ubuntu:
> Fix Released
> Status in linux source package in Jammy:
> Fix Committed
>
> Bug description:
> BugLink: https://bugs.launchpad.net/bugs/2068738
>
> [Impact]
>
> On systems with AMD Picasso/Raven 2 GPU devices, when the IOMMU is
> enabled, the system fails to boot correctly, and all users see is a
> black screen.
>
> This is caused by a null pointer dereference when enabling the IOMMU
> after the device has been initialised. It should happen the other way
> around.
>
> AMD-Vi: AMD IOMMUv2 loaded and initialized
> ...
> amdgpu: Topology: Add APU node [0x15d8:0x1002]
> kfd kfd: amdgpu: added device 1002:15d8
> kfd kfd: amdgpu: Failed to resume IOMMU for device 1002:15d8
> ...
> amdgpu 0000:06:00.0: amdgpu: amdgpu_device_ip_init failed
> amdgpu 0000:06:00.0: amdgpu: Fatal error during GPU init
> amdgpu 0000:06:00.0: amdgpu: amdgpu: finishing device.
> ...
> BUG: kernel NULL pointer dereference, address: 000000000000013c
> ...
> CPU: 1 PID: 223 Comm: systemd-udevd Not tainted 5.15.0-112-generic
> #122-Ubuntu
> ...
> RIP: 0010:amdgpu_dm_fini+0x149/0x1f0 [amdgpu]
> ...
> Call Trace:
> <TASK>
> ? srso_return_thunk+0x5/0x10
> ? show_trace_log_lvl+0x28e/0x2ea
> ? show_trace_log_lvl+0x28e/0x2ea
> ? dm_hw_fini+0x23/0x30 [amdgpu]
> ? show_regs.part.0+0x23/0x29
> ? __die_body.cold+0x8/0xd
> ? __die+0x2b/0x37
> ? page_fault_oops+0x13b/0x170
> ? srso_return_thunk+0x5/0x10
> ? do_user_addr_fault+0x321/0x670
> ? srso_return_thunk+0x5/0x10
> ? __free_pages_ok+0x34a/0x4f0
> ? exc_page_fault+0x77/0x170
> ? asm_exc_page_fault+0x27/0x30
> ? amdgpu_dm_fini+0x149/0x1f0 [amdgpu]
> dm_hw_fini+0x23/0x30 [amdgpu]
> amdgpu_device_ip_fini_early.isra.0+0x278/0x312 [amdgpu]
> amdgpu_device_fini_hw+0x156/0x208 [amdgpu]
> amdgpu_driver_unload_kms+0x69/0x90 [amdgpu]
> amdgpu_driver_load_kms.cold+0x81/0x107 [amdgpu]
> amdgpu_pci_probe+0x1d1/0x290 [amdgpu]
> local_pci_probe+0x4b/0x90
> ? srso_return_thunk+0x5/0x10
> pci_device_probe+0x119/0x200
> really_probe+0x222/0x420
> __driver_probe_device+0xe8/0x140
> driver_probe_device+0x23/0xc0
> __driver_attach+0xf7/0x1f0
> ? __device_attach_driver+0x140/0x140
> bus_for_each_dev+0x7f/0xd0
> driver_attach+0x1e/0x30
> bus_add_driver+0x148/0x220
> ? srso_return_thunk+0x5/0x10
> driver_register+0x95/0x100
> __pci_register_driver+0x68/0x70
> amdgpu_init+0x7c/0x1000 [amdgpu]
> ? 0xffffffffc0e0b000
> do_one_initcall+0x49/0x1e0
> ? srso_return_thunk+0x5/0x10
> ? kmem_cache_alloc_trace+0x19e/0x2e0
> do_init_module+0x52/0x260
> load_module+0xb45/0xbe0
> __do_sys_finit_module+0xbf/0x120
> __x64_sys_finit_module+0x18/0x20
> x64_sys_call+0x1ac3/0x1fa0
> do_syscall_64+0x56/0xb0
> ...
> entry_SYSCALL_64_after_hwframe+0x67/0xd1
>
> A workaround does exist. Users can set "nomodeset" or "amd_iommu=off"
> to GRUB_CMDLINE_LINUX_DEFAULT, update-grub and reboot.
>
> [Fix]
>
> The regression was caused by the following commit that landed in
> 5.15.0-112-generic, and 5.15.150 upstream:
>
> commit 3c7e53c0d4b43ffe6e7715414b5f2b3177881ecd ubuntu-jammy
> Author: Yifan Zhang <email address hidden>
> Date: Tue Sep 28 15:42:35 2021 +0800
> Subject: drm/amdgpu: init iommu after amdkfd device init
> Link:
> https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy/commit/?id=3c7e53c0d4b43ffe6e7715414b5f2b3177881ecd
>
> The fix is to revert this patch, as it was not suppose to be
> backported to 5.15 stable.
>
> The mailing list discussion with AMD developers is:
>
> https://<email address hidden>/
>
> The fix hasn't been acknowledged by Greg KH or Sasha Levin yet, so
> sending as a Ubuntu SAUCE patch. If the upstream status changes, we
> can NAK and resend.
>
> [Testcase]
>
> You need a system with an AMD Picasso/Raven 2 device. It will likely
> be an APU, and not a discrete graphics card, but any AMD Picasso/Raven
> 2 device is affected.
>
> Install the kernel and boot. Make sure full modesetting is enabled.
>
> There is a test kernel available in the ppa below:
>
> https://launchpad.net/~mruffell/+archive/ubuntu/lp2068738-test
>
> If you install the test kernel, your system should boot successfully.
>
> [Where problems could occur]
>
> We are reverting a problematic patch and going back to how it was
> before 5.15.0-112-generic. This should not cause any issues for users.
>
> If a regression were to occur, users can set "nomodeset" or
> "amd_iommu=off" to GRUB_CMDLINE_LINUX_DEFAULT and reboot, or pin their
> kernel to a working one.
>
> The impact of a regression would be high, as users displays could be
> blank.
>
> [Other Info]
>
> User reports:
> https://forums.linuxmint.com/viewtopic.php?t=421484
> https://forums.linuxmint.com/viewtopic.php?t=421441
>
> https://www.reddit.com/r/Ubuntu/comments/1d9uviz/had_to_purge_kernel_5150112_could_not_boot/
>
> https://www.reddit.com/r/linuxmint/comments/1d9w6c9/kernel_5150112_boot_failure/
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2068735
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2068793
> https://bugs.launchpad.net/bugs/2068812
>
> As bizarre as it is, this commit was actually originally included in
> 5.15-rc5:
>
> commit 714d9e4574d54596973ee3b0624ee4a16264d700
> Author: Yifan Zhang <email address hidden>
> Date: Tue Sep 28 15:42:35 2021 +0800
> Subject: drm/amdgpu: init iommu after amdkfd device init
> Link:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=714d9e4574d54596973ee3b0624ee4a16264d700
>
> It seems to have caused issues back then too, and was removed in the
> following fixups, in 5.16-rc1:
>
> commit 93cec184788b0cf3926bc1f7b47fed74ba87990c
> Author: James Zhu <email address hidden>
> Date: Tue Nov 2 21:33:50 2021 -0400
> Subject: drm/amdgpu: remove duplicated kfd_resume_iommu
> Link:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=93cec184788b0cf3926bc1f7b47fed74ba87990c
>
> commit 9f4f2c1a35248f56b2a9c1c004e0aaff3609b15d
> Author: shaoyunl <email address hidden>
> Date: Fri Nov 5 12:34:14 2021 -0400
> Subject: drm/amd/amdgpu: fix the kfd pre_reset sequence in sriov
> Link:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9f4f2c1a35248f56b2a9c1c004e0aaff3609b15d
>
> I'm not exactly in favor of rewriting history twice, so I think we
> should just revert the upstream stable patch and move on.
>
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>
>