CVE-2026-23127

CVE-2026-23127 affects the Linux kernel perf subsystem. The issue is caused by a refcount warning in perf_mmap_rb() when updating event->mmap_count during group-member mmap creation with PERF_FLAG_FD_OUTPUT. Specifically, refcount_inc(&event->mmap_count) can run when mmap_count is 0, trigge...