CVE-2026-90247

/// Technical description

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

bpf: Fix mmap_lock leak in irq_work path

stack_map_get_build_id_offset() introduced a per-CPU irq_work to defer

mmap_read_unlock() from NMI context, and bpf_find_vma() later reused the

same mmap_unlock_work. Both callers only check whether the work is busy

before taking mmap_lock, so a nested caller can reuse the slot before the

first caller queues it. Two read locks may then be acquired while only one

deferred unlock runs, leaking a read lock and blocking exit_mmap().

Reserve the per-CPU slot before mmap_read_trylock(). Use the same wrapper

in stackmap and bpf_find_vma() so both callers release the reservation on

trylock failure. Keep rejecting the slot while the irq_work remains busy.

Release it after the irq_work callback unlocks the mm.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References