bpf: Fix mmap_lock leak in irq_work path

Answer in brief

CVE-2026-90247 records a Unknown severity vulnerability in bpf: Fix mmap_lock leak in irq_work path. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 17, 2026Updated Sep 17, 2026Source checked Sep 17, 2026First seen by HOL Sep 17, 2026Material review Sep 17, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=eac9153f2b584c702cea02c1f1a57d85aa9aea42 <a052ad5edccf5319f50ed955de4368f8318a9f20 \|\| >=eac9153f2b584c702cea02c1f1a57d85aa9aea42 <051f2da26ce377f683b938a3382e0f16d02f3139 \|\| >=eac9153f2b584c702cea02c1f1a57d85aa9aea42 <fa9dcacdcdf487f0ffef64bf67622f1caed509f1 \|\| a7f4da875c16f3b8bef0d9ec67528111045bfcd8 \|\| f1838da73cccb238b8be4ef464fce0168dc7ba84 \|\| >=4.19.92 <4.20 \|\| >=5.4.7 <5.5	a052ad5edccf5319f50ed955de4368f8318a9f20, 051f2da26ce377f683b938a3382e0f16d02f3139, fa9dcacdcdf487f0ffef64bf67622f1caed509f1, 4.20, 5.5
Linux/Linuxgeneric	5.5	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to a052ad5edccf5319f50ed955de4368f8318a9f20 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 17, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.