CVE-2026-74337bpf: 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.

CVSS

Not yet scored

Weakness (CWE)

Not given

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Linux

NVD analysis

Received

Record last updated

Aug 17, 2026

First seen by InfoSec Signals

Oct 9, 2026

The CVE record on cve.org · NVD's entry

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