Description
In the Linux kernel, the following vulnerability has been resolved:

s390/pai: Handle multiple PMU stop callback invocations

Handle the following scenario:
The kernel protects itself against a very high sampling load and
throttles the sampling using:

perf_event_throttle() --> PMU->stop()

Shortly later the scheduler may terminate the task and removes it from the
CPU. It again calls

PMU->stop()

which results in two invocations of PMU->stop() called back to back.
Protect against this and check the PERF_HES_STOPPED bit on function
entry. If it is already set return.
Clear bit PERF_HES_STOPPED in PMU->start().

Prohibit ioctl(fd, PERF_EVENT_IOC_PERIOD, ...) call for this event.
It sets perf_event::event_limit to a positive value and causes
perf_event_overflow() to invoke pai_stop() call back function when
perf_event::event_limit hits zero. This is not supported because the
sample events CRYPTO_ALL and NNPA_ALL are only taken at schedule out
of a task.

Use list_for_each_entry_safe() for safe iteration over syswide_list
in pai_have_samples().
Published: 2026-10-28
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Wed, 28 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
First Time appeared Linux linux
Vendors & Products Linux linux

Wed, 28 Oct 2026 12:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-665

Wed, 28 Oct 2026 10:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: s390/pai: Handle multiple PMU stop callback invocations Handle the following scenario: The kernel protects itself against a very high sampling load and throttles the sampling using: perf_event_throttle() --> PMU->stop() Shortly later the scheduler may terminate the task and removes it from the CPU. It again calls PMU->stop() which results in two invocations of PMU->stop() called back to back. Protect against this and check the PERF_HES_STOPPED bit on function entry. If it is already set return. Clear bit PERF_HES_STOPPED in PMU->start(). Prohibit ioctl(fd, PERF_EVENT_IOC_PERIOD, ...) call for this event. It sets perf_event::event_limit to a positive value and causes perf_event_overflow() to invoke pai_stop() call back function when perf_event::event_limit hits zero. This is not supported because the sample events CRYPTO_ALL and NNPA_ALL are only taken at schedule out of a task. Use list_for_each_entry_safe() for safe iteration over syswide_list in pai_have_samples().
Title s390/pai: Handle multiple PMU stop callback invocations
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-28T10:34:40.025Z

Reserved: 2026-09-25T10:25:14.393Z

Link: CVE-2026-99125

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-28T11:17:32.210

Modified: 2026-10-28T11:17:32.210

Link: CVE-2026-99125

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-28T12:15:14Z

Weaknesses