Undetected Data corruption in MPI workloads that use VSX for reductions on POWER9 DD2.1 systems
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
The Ubuntu-power-systems project |
Fix Released
|
High
|
Patricia Domingues | ||
linux (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned | ||
Focal |
Fix Released
|
Undecided
|
Unassigned | ||
Groovy |
Fix Released
|
Undecided
|
Unassigned | ||
Hirsute |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
SRU Justification:
[Impact]
* A data integrity issue was observed on POWER 9 (DD2.1) systems.
* It affects Ubuntu 20.04 with kernel 5.4.0-52 and Ubuntu 20.10 with kernel 5.8.0-26 kernel.
* The root cause is found in the compiling of p9_hmi_
* When doing a VMX store (in __get_user_
[Fix]
* 1da4a0272c54 "powerpc: Fix undetected data corruption with P9N DD2.1 VSX CI load emulation"
* d1781f237047 "selftests/powerpc: Make alignment handler test P9N DD2.1 vector CI load workaround"
[Test Case]
* A POWER 9 (DD2.1) bare metal system is needed that has either Ubuntu 20.04, 20.10 or 21.04 installed.
* It's best to test this based on a sample application and test case
"selftests/
[Regression Potential]
* The regression risk is relatively moderate, because:
* it only happens with special VSX (vector) instructions in use, e.g. in p9_hmi_special_emu
* it happens on bare metal only and only on POWER 9 (DD2.1)
* and the changes are very overseeable (in total one effective code line per patch/commit)
* Since only p9_hmi_special_emu is touched, this will break in case of any regressions, but this is already broken based on this bug.
[Other]
* According to the reporter this affects Ubuntu 20.04 / 5.4.0-52 and 20.10 / 5.8.0-26.
* Since the development of Hirsute is already open the SRU is requested for Hirsute, too.
* Patches got upstream accepted in v5.10-rc1 and v5.10-rc2.
CVE References
tags: | added: architecture-ppc64le bugnameltc-189000 severity-medium targetmilestone-inin2010 |
Changed in ubuntu: | |
assignee: | nobody → Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) |
affects: | ubuntu → linux (Ubuntu) |
tags: |
added: severity-high removed: severity-medium |
description: | updated |
summary: |
- Ubuntu 20.10- Undetected Data corruption in MPI workloads that use VSX - for reductions on POWER9 DD2.1 systems + Undetected Data corruption in MPI workloads that use VSX for reductions + on POWER9 DD2.1 systems |
Changed in ubuntu-power-systems: | |
assignee: | Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) → Patricia Domingues (patriciasd) |
Changed in linux (Ubuntu Groovy): | |
status: | In Progress → Fix Committed |
Changed in linux (Ubuntu Focal): | |
status: | In Progress → Fix Committed |
Changed in ubuntu-power-systems: | |
status: | In Progress → Fix Released |
Even if this was submitted as medium, I bump it to high.