bpf: Fix NMI/tracepoint re-entry deadlock on lru locks
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix NMI/tracepoint re-entry deadlock on lru locks NMI and tracepoint BPF programs can re-enter the per-CPU or global LRU lock that bpf_lru_pop_free()/push_free() already hold on the same CPU, AA-deadlocking. Lockdep reports "inconsistent {INITIAL USE} -> {IN-NMI}" on &l->lock (syzbot c69a0a2c816716f1e0d5) and "possible recursive locking detected" on &loc_l->lock (syzbot 18b26edb69b2e19f3b33). Prior trylock and rqspinlock based fixes (see links) were nacked because compromised on reliability. This patch converts every LRU lock site to rqspinlock_t and adds a recovery path for some failure windows to avoid node leaks. Failure recovery: - *_pop_free top-level: return NULL; prealloc_lru_pop() already treats that as no-free-element (-ENOMEM). - Cross-CPU steal: skip the victim's locked loc_l, try next CPU. - Post-steal local lock fail: publish stolen node to lockless per-CPU free_llist; next pop on this CPU picks it up. - push_free fail: mark node pending_free=1. __local_list_flush(), __local_list_pop_pending() reclaim the node from pending_list. __bpf_lru_list_shrink_inactive() reclaims the node from inactive list. Nodes from active list are reclaimed by __bpf_lru_list_shrink() or after __bpf_lru_list_rotate_active() demotes it to the inactive.
- Published
- Aug 15, 2026
- Updated
- Aug 17, 2026
- EPSS
- 0.2% · 10th percentile
- CWE
- —
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Report tools
Action score
0
Monitor
Low priority for now.
- CVSS
- 0 / 40 · —
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
Affected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 4.10affected
- 3a08c2fd763450a927d1130de078d6f9e74944fb and later · before 8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5affected · git
- 3a08c2fd763450a927d1130de078d6f9e74944fb and later · before 440a2fdbb40608d55a7b11f2be53592a3785131daffected · git
- 3a08c2fd763450a927d1130de078d6f9e74944fb and later · before 89edbdfc5d0308cef57b71359331de5c4ddbf763affected · git
- before 4.10not affected · semver
- 6.18.40 and later · up to and including 6.18.*not affected · semver
- 7.1.5 and later · up to and including 7.1.*not affected · semver
- 7.2 and laternot affected · original_commit_for_fix
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | all versions | — |
| Debian:14 | linux | before 7.1.5-1 | 7.1.5-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
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Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 440a2fdbb40608d55a7b11f2be53592a3785131d | Vendor (CNA) |
| Linux Linux | 89edbdfc5d0308cef57b71359331de5c4ddbf763 | Vendor (CNA) |
| Linux Linux | 8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5 | Vendor (CNA) |
| debian:linux | 7.1.5-1 · Debian:14 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
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Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
No CVSS vector for this record, so attack conditions can't be derived.
Weakness class (CWE)
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Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
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We use this product, ask for helpChange log
- Fix✗ → ✓
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References
- git.kernel.org/stable/c/440a2fdbb40608d55a7b11f2be53592a3785131d
- git.kernel.org/stable/c/89edbdfc5d0308cef57b71359331de5c4ddbf763
- git.kernel.org/stable/c/8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5
Vendor advisories and official records. Exploit/PoC links are deliberately left out.