{"id":"CVE-2026-74337","summary":"bpf: Fix NMI/tracepoint re-entry deadlock on lru locks","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix NMI/tracepoint re-entry deadlock on lru locks\n\nNMI and tracepoint BPF programs can re-enter the per-CPU or global\nLRU lock that bpf_lru_pop_free()/push_free() already hold on the\nsame CPU, AA-deadlocking. Lockdep reports \"inconsistent\n{INITIAL USE} -\u003e {IN-NMI}\" on &l-\u003elock (syzbot c69a0a2c816716f1e0d5)\nand \"possible recursive locking detected\" on &loc_l-\u003elock (syzbot\n18b26edb69b2e19f3b33).\n\nPrior trylock and rqspinlock based fixes (see links) were nacked\nbecause compromised on reliability.\n\nThis patch converts every LRU lock site to rqspinlock_t and adds a\nrecovery path for some failure windows to avoid node leaks.\n\nFailure recovery:\n\n - *_pop_free top-level: return NULL; prealloc_lru_pop() already\n   treats that as no-free-element (-ENOMEM).\n\n - Cross-CPU steal: skip the victim's locked loc_l, try next CPU.\n\n - Post-steal local lock fail: publish stolen node to lockless\n   per-CPU free_llist; next pop on this CPU picks it up.\n\n - push_free fail: mark node pending_free=1. __local_list_flush(),\n   __local_list_pop_pending() reclaim the node from pending_list.\n   __bpf_lru_list_shrink_inactive() reclaims the node from inactive\n   list. Nodes from active list are reclaimed by __bpf_lru_list_shrink()\n   or after __bpf_lru_list_rotate_active() demotes it to the inactive.","modified":"2026-08-16T03:48:27.739713096Z","published":"2026-08-15T05:58:28.518Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74337.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/440a2fdbb40608d55a7b11f2be53592a3785131d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/89edbdfc5d0308cef57b71359331de5c4ddbf763"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74337.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74337"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3a08c2fd763450a927d1130de078d6f9e74944fb"},{"fixed":"8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5"},{"fixed":"440a2fdbb40608d55a7b11f2be53592a3785131d"},{"fixed":"89edbdfc5d0308cef57b71359331de5c4ddbf763"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74337.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.10.0"},{"fixed":"6.18.40"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74337.json"}}],"schema_version":"1.9.0"}