This commit appeared now in v5.15.46, which will be handled in the next
weeks by the kernel team.
But I change the title to 22.04, since 21.10 is EOL as of today, and this patch
is not in jammy.
It got upstream accepted with v5.19-rc1 hence no need to patch kinetic, since
kinetic's target kernel is 5.19.
** Changed in: ubuntu-z-systems
Status: New => Triaged
** Changed in: linux (Ubuntu)
Status: New => Triaged
** Also affects: linux (Ubuntu Jammy)
Importance: Undecided
Status: New
** Changed in: linux (Ubuntu Jammy)
Status: New => Triaged
** Changed in: linux (Ubuntu)
Status: Triaged => Invalid
** Changed in: linux (Ubuntu Jammy)
Assignee: (unassigned) => Skipper Bug Screeners (skipper-screen-team)
** Changed in: linux (Ubuntu)
Assignee: Skipper Bug Screeners (skipper-screen-team) => (unassigned)
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https://bugs.launchpad.net/bugs/1977962
Title:
[UBUNTU 21.10] s390/perf: obtain sie_block from the right address
Status in Ubuntu on IBM z Systems:
Triaged
Status in linux package in Ubuntu:
Invalid
Status in linux source package in Jammy:
Triaged
Bug description:
Description: s390/perf: obtain sie_block from the right address
Symptom: Read from unitialized stack memory, incorrect guest
perf data reported, possibly system crash.
Problem: When perf is instructed to record a software-based event and
to trace the guest, i.e. using the following command:
perf kvm --guest --guestvmlinux=endless.elf top -e cpu-clock
The reported guest instruction pointer is inaccurate or
the system may crash.
This is caused by the sie_block being taken from empty1[0]
in sie_block() in arch/s390/kernel/perf_event.c, but since
1179f170b6f0 ("s390: fix fpu restore in entry.S")
it resides at empty1[1].
Solution: Obtain sie_block from the right address in sie_block().
Reproduction: 1. Start a KVM guest executing an endless loop.
2. Determine the instruction address of the loop.
3. Start perf recording for any software event and trace
the guest, for example using this command:
perf kvm --guest --guestvmlinux=endless.elf top -e
cpu-clock
4. The reported guest instruction addresses don't match
the loop's instruction address or the system crashes.
Upstream-ID: c9bfb460c3e4da2462e16b0f0b200990b36b1dd2
BBPF Probl.ID: 198450
Preventive: yes
Reported: -
SupportTicket: -
Reference: -
Date: 2022-06-02
Author: [email protected]
Component: kernel
Link:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c9bfb460c3e4da2462e16b0f0b200990b36b1dd2
Problem occurs / affects impish and jammy
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