CVE-2026-98268

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

perf: Fix null pointer access in is_include_guest_event()

A typical module unload occurring event when there is an active perf connection leads to freeing of the pmu pointer. The call log is something like: .. __pmu_detach_event pmu_detach_event pmu_detach_events perf_pmu_unregister ..

__pmu_detach_event() sets event->pmu to null. When the perf connection finally is closed, the following stack trace is observed:

Oops: general protection fault, kernel NULL pointer dereference … RIP: 0010:_free_event+0x3e/0x370 … Call Trace: … perf_event_release_kernel+0x260/0x2d0 perf_release+0x12/0x20

A call to mediated_pmu_unaccount_event() inside _free_event() is the root cause of this crash. Adding a check inside is_include_guest_event() ensures we dont accidentally access a null pmu ptr. In addition to this, we will now call mediated_pmu_unaccount_event() before clearing the pmu ptr so that nr_include_guest_events counts are maintained correctly.

Affected Software

References

• https://git.kernel.org/stable/c/7fa9a465ae8f07c0e4685db6edb6a6f984dbd784
• https://git.kernel.org/stable/c/88aed0422f39b22406f35f1e758cea25e7bbcfb5