hisilicon hibmc regression due to ea642c3216cb ("drm/ttm: add io_mem_pfn callback")
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Linux |
New
|
Undecided
|
Unassigned | ||
linux (Ubuntu) |
Fix Released
|
Undecided
|
Daniel Axtens | ||
Artful |
Fix Released
|
Undecided
|
Unassigned | ||
Bionic |
Fix Released
|
Undecided
|
Daniel Axtens |
Bug Description
[SRU Justification]
[Impact]
On Artful and Bionic kernels, X fails to start and a kernel splat is printed.
This is cbecause ea642c3216cb ("drm/ttm: add io_mem_pfn callback") is incomplete: the hisilicon hibmc driver does not contain the callback and so the kernel tries to execute code at NULL.
[Fix]
Bionic: There is a generic fix in 4.16 at c67fa6edc8b11af
Artful: Rather than a generic fix, I have submitted a very very minimal fix that only touches hibmc.
[Regression Potential]
Artful: Minimal - fix only touches hibmc driver. Tested on D05 board.
Bionic: fix is to generic drm code, but is small and easily reviewable.
[Testcase]
Install patched kernel, try to start X. If it succeeds, the fix works. If there's a kernel splat, the fix does not work.
[Notes]
Artful: HiSilicon would really like this fix in Artful in such time so that when the next 16.04 point release ships, the HWE kernel will work with Xorg.
Bionic: no extra notes.
CVE References
description: | updated |
Changed in linux (Ubuntu Artful): | |
status: | New → Fix Committed |
description: | updated |
Changed in linux (Ubuntu Bionic): | |
status: | Confirmed → Fix Committed |
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 1738334
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.