CVE-2026-99187

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

perf: Fix perf pmu migrate context() leaving events behind

perf pmu remove() walks the group leaders of a CPU and PMU with perf event groups for cpu pmu(), removing each one as it goes. perf remove from context() takes the leader out of the groups rbtree, after which rb next() on that node returns NULL, prematurely ending the walk. Other groups stay behind in the source context.

On CPU hotplug, they are then torn down with the dying CPU. They keep running until teardown, while the PMU's interrupt and migrated events are on a new CPU, which drivers rely on never happening.

Walk ctx->event list instead and pick out the PMU's events by their pmu ctx.