GHSA-83qv-jr76-p4xc

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().

UBUNTU-CVE-2026-99125

Affected: Ubuntu:Pro:14.04:LTS: linux, Ubuntu:Pro:14.04:LTS: linux-aws, Ubuntu:Pro:14.04:LTS: linux-azure, Ubuntu:Pro:14.04:LTS: linux-lts-xenial, Ubuntu:Pro:16.04:LTS: linux, Ubuntu:Pro:16.04:LTS: linux-aws, Ubuntu:Pro:16.04:LTS: linux-aws-hwe, Ubuntu:Pro:16.04:LTS: linux-azure, Ubuntu:Pro:16.04:LTS: linux-gcp, Ubuntu:Pro:16.04:LTS: linux-hwe and 257 more

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().

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GHSA-83qv-jr76-p4xc

UBUNTU-CVE-2026-99125