lttng-modules 2.10.8-1ubuntu2~18.04.1 ADT test failure with linux-kvm 4.15.0-1059.60
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
lttng-modules (Ubuntu) |
Won't Fix
|
Medium
|
Unassigned | ||
Xenial |
Fix Released
|
Medium
|
Stefan Bader | ||
Bionic |
Fix Released
|
Medium
|
Stefan Bader | ||
Eoan |
Fix Released
|
Medium
|
Stefan Bader | ||
Focal |
Fix Released
|
Medium
|
Stefan Bader |
Bug Description
Testing failed on:
amd64: https:/
[SRU Justification]
== Impact ==
In linux 5.6 upstream replaced vmalloc_sync_all() by vmalloc_
Recent stable updates backported that change into 4.4, 4.15, 5.3, and 5.4. This affects lttng-modules. Either the build fails completely (if kallsyms is not enabled). Or there will be warnings at runtime:
LTTng: vmalloc_sync_all symbol lookup failed.
Page fault handler and NMI tracing might trigger faults.
== Fix ==
Backporting 4 patches from upstream lttng fixes the issue for 4.4 and 5.4 (as those allow matching against linux kernel version). For 4.15 and 5.3 and additional patch adds Ubuntu specific version ranges.
Note, that this last patch also adds a range for 5.0 which was Disco. This should not hurt and also indirectly is needed for some backport kernels in 18.04/Bionic. But I want to try keeping the patches as similar as possible across releases.
== Testcase ==
Installation of lttng-modules-dkms, depending on kernel configuration either the build will fail or loading lttng-test (or checking dmesg after reboot) will show warnings.
With the changes applied the build succeeds in all cases and no warnings appear.
== Regression Potential ==
Low, without the new function name present, everything would be unchanged and once the change is there, functionality already is regressed.
tags: | added: patch |
Changed in lttng-modules (Ubuntu): | |
status: | New → Triaged |
importance: | Undecided → Medium |
Changed in lttng-modules (Ubuntu Xenial): | |
importance: | Undecided → Medium |
status: | New → Triaged |
Changed in lttng-modules (Ubuntu Bionic): | |
status: | New → Triaged |
Changed in lttng-modules (Ubuntu Eoan): | |
status: | New → Triaged |
Changed in lttng-modules (Ubuntu Focal): | |
status: | New → Triaged |
Changed in lttng-modules (Ubuntu Bionic): | |
importance: | Undecided → Medium |
Changed in lttng-modules (Ubuntu Eoan): | |
importance: | Undecided → Medium |
Changed in lttng-modules (Ubuntu Focal): | |
importance: | Undecided → Medium |
description: | updated |
description: | updated |
description: | updated |
Changed in lttng-modules (Ubuntu Bionic): | |
assignee: | nobody → Stefan Bader (smb) |
status: | Triaged → In Progress |
Implicit function declaration error due to missing "vmalloc_ sync_all( )" is expected due to a recent change in the kernel ABI in Bionic:
https:/ /git.launchpad. net/~ubuntu- kernel/ ubuntu/ +source/ linux/+ git/bionic/ commit/ ?id=a37c73d3e2f b62bf486c0d2099 deff8fad325f20