jammy 5.15 kernel soft lockup when zfs.ko is loaded on s390x w/ gcc >= 11.2.0-10ubuntu1 / gcc-11 PLT regression on s390x
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Ubuntu on IBM z Systems |
Fix Released
|
Critical
|
bugproxy | ||
gcc-11 (Ubuntu) |
Fix Released
|
Critical
|
Unassigned | ||
Impish |
Invalid
|
Undecided
|
Unassigned | ||
Jammy |
Fix Released
|
Critical
|
Unassigned | ||
linux (Ubuntu) |
Fix Released
|
Critical
|
Unassigned | ||
Impish |
Fix Released
|
High
|
Unassigned | ||
Jammy |
Fix Released
|
Critical
|
Unassigned |
Bug Description
[Impact]
Installing zfs-dkms seems to trigger a soft lockup issue as soon as zfs.ko is loaded. When the soft lockup happens the system isn't reachable anymore via ssh and on the console we can see some exlicit rcu stall warnings.
This seems to happen only when zfs is compile with gcc >= 11.2.0-10ubuntu1. Downgrading gcc to previous versions doesn't show the problem and zfs is working just fine.
[Test case]
On s390x install the latest 5.15 Jammy kernel and run:
apt install zfs-dkms
[Fix]
Temporary workaround is to build zfs with gcc-10 on s390x.
[Regression potential]
Building a kernel module with a different compiler is never 100% safe, we may experience potential crashes / panics if the ABI is not compatible. Moreover, if we build zfs with gcc-10 we are going to lose some of the performance benefits provided by gcc-11.
However these regressions are limited to zfs on s390x and without this change zfs is broken anyway on this architecture.
[Further analysis]
@IBM
Issue report to zfs upstream at https:/
Reverting https:/
Please bring this issue to the attention of Ilya Leoshkevich
Potentially this means we may have missbuilt userspace binaries in the archive for s390x.
CVE References
tags: | added: patch |
description: | updated |
description: | updated |
summary: |
- jammy 5.15 soft lockup when zfs.ko is loaded on s390x + jammy 5.15 kernel soft lockup when zfs.ko is loaded on s390x w/ gcc >= + 11.2.0-10ubuntu1 |
Changed in gcc-11 (Ubuntu Jammy): | |
importance: | Undecided → Critical |
Changed in zfs-linux (Ubuntu Jammy): | |
importance: | Undecided → Critical |
assignee: | nobody → Andrea Righi (arighi) |
summary: |
jammy 5.15 kernel soft lockup when zfs.ko is loaded on s390x w/ gcc >= - 11.2.0-10ubuntu1 + 11.2.0-10ubuntu1 / gcc-11 PLT regression on s390x |
description: | updated |
tags: | added: s390x |
Changed in ubuntu-z-systems: | |
assignee: | nobody → bugproxy (bugproxy) |
importance: | Undecided → Critical |
Changed in gcc-11 (Ubuntu Jammy): | |
status: | New → Confirmed |
Changed in ubuntu-z-systems: | |
status: | New → Confirmed |
Changed in linux (Ubuntu Impish): | |
status: | New → Fix Committed |
Changed in gcc-11 (Ubuntu Impish): | |
status: | New → Invalid |
Moving to Debian zfs 2.1.1 + applying the debdiff in attach seems to fix the problem.