[UBUNTU 18.04] zpcictl --reset - contribution for kernel
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Ubuntu on IBM z Systems |
Fix Released
|
Undecided
|
Skipper Bug Screeners | ||
linux (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned | ||
Bionic |
Fix Released
|
Undecided
|
Unassigned | ||
Eoan |
Fix Released
|
Undecided
|
Unassigned | ||
Focal |
Fix Released
|
Undecided
|
Unassigned | ||
Groovy |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
SRU Justification:
==================
[Impact]
* With zpci_disable() working, 'lockdep' detected a potential deadlock (in the s390x zPCI subsystem).
* The deadlock is between recovering a PCI function via the /sys/bus/
[Fix]
* Backport 1: https:/
* Backport 2: https:/
[Test Case]
* It's best to (re-)test using the kernel's locking validator, also known as 'lockdep'.
* Since this potential deadlock was identified by lockdep.
[Regression Potential]
* The regression potential can be considered as moderate, since:
* It is purely s390x specific code (arch/s390/
* It only affects the zPCI, the s390x specific PCI code layer.
* PCI cards available for s390x are optional cards (RoCE and zEDC) and not very wide-spread.
* The states between such a deadlock can happen (recover and power off) are non standard and usually undesired states.
* The patches are upstream accepted since 5.6 and already landed in eoan and focal.
[Other Info]
* Patches 17cdec960cf7 "s390/pci: Recover handle in clp_set_pci_fn()" and 576c75e36c68 "s390/pci: Fix possible deadlock in recover_store()" are upstream accepted since kernel 5.6, but they don't apply cleanly on bionic master-next, hence backports are needed:
* 0001-s390-
* 0001-s390-
* Both patches/commits already landed in focal (with LP 1863768) and in eoan (with LP 1868324).
__________
This Bug tracks the necessary backport for the Linux Kernel
to enable proper reset/recovery of PCI Functions in the error state.
There is a related fix to s390-tools but the relevant zpcictl command
is not part of Ubuntu 18.04
Upstream this includes the following commits:
In the Kernel:
17cdec960cf776b
Backport patch attached.
576c75e36c689be
applies cleanly but for the second a small backport change is necessary.
These fixes are already in 20.04 but need also be applied to 18.04.
CVE References
Changed in ubuntu-z-systems: | |
status: | New → Triaged |
assignee: | nobody → Skipper Bug Screeners (skipper-screen-team) |
Changed in linux (Ubuntu): | |
assignee: | Skipper Bug Screeners (skipper-screen-team) → Canonical Kernel Team (canonical-kernel-team) |
Changed in linux (Ubuntu): | |
status: | New → Fix Released |
Changed in linux (Ubuntu Bionic): | |
status: | New → Confirmed |
Changed in ubuntu-z-systems: | |
status: | Triaged → Confirmed |
Changed in linux (Ubuntu Eoan): | |
status: | New → Fix Released |
Changed in linux (Ubuntu Focal): | |
status: | New → Fix Released |
Changed in linux (Ubuntu Eoan): | |
status: | Fix Released → New |
Changed in linux (Ubuntu Eoan): | |
status: | New → Fix Released |
description: | updated |
Changed in linux (Ubuntu Bionic): | |
status: | Confirmed → In Progress |
Changed in ubuntu-z-systems: | |
status: | Confirmed → In Progress |
Changed in linux (Ubuntu Bionic): | |
status: | In Progress → Fix Committed |
Changed in ubuntu-z-systems: | |
status: | In Progress → Fix Committed |
Changed in ubuntu-z-systems: | |
status: | Fix Committed → Fix Released |
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