{"id":"CVE-2026-74337","state":"PUBLISHED","title":"bpf: Fix NMI/tracepoint re-entry deadlock on lru locks","description":"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} -> {IN-NMI}\" on &l->lock (syzbot c69a0a2c816716f1e0d5)\nand \"possible recursive locking detected\" on &loc_l->lock (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.","publishedAt":"2026-08-15T05:58:28.518Z","updatedAt":"2026-08-17T05:17:29.070Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3a08c2fd763450a927d1130de078d6f9e74944fb","status":"affected","lessThan":"8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5","versionType":"git"},{"version":"3a08c2fd763450a927d1130de078d6f9e74944fb","status":"affected","lessThan":"440a2fdbb40608d55a7b11f2be53592a3785131d","versionType":"git"},{"version":"3a08c2fd763450a927d1130de078d6f9e74944fb","status":"affected","lessThan":"89edbdfc5d0308cef57b71359331de5c4ddbf763","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/bpf_lru_list.c","kernel/bpf/bpf_lru_list.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.10","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/bpf_lru_list.c","kernel/bpf/bpf_lru_list.h"]}],"references":["https://git.kernel.org/stable/c/8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5","https://git.kernel.org/stable/c/440a2fdbb40608d55a7b11f2be53592a3785131d","https://git.kernel.org/stable/c/89edbdfc5d0308cef57b71359331de5c4ddbf763"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74337.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74337","state":"PUBLISHED","datePublished":"2026-08-15T05:58:28.518Z","dateUpdated":"2026-08-17T05:17:29.070Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.885Z"},"containers":{"cna":{"title":"bpf: Fix NMI/tracepoint re-entry deadlock on lru locks","descriptions":[{"lang":"en","value":"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} -> {IN-NMI}\" on &l->lock (syzbot c69a0a2c816716f1e0d5)\nand \"possible recursive locking detected\" on &loc_l->lock (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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3a08c2fd763450a927d1130de078d6f9e74944fb","status":"affected","lessThan":"8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5","versionType":"git"},{"version":"3a08c2fd763450a927d1130de078d6f9e74944fb","status":"affected","lessThan":"440a2fdbb40608d55a7b11f2be53592a3785131d","versionType":"git"},{"version":"3a08c2fd763450a927d1130de078d6f9e74944fb","status":"affected","lessThan":"89edbdfc5d0308cef57b71359331de5c4ddbf763","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/bpf_lru_list.c","kernel/bpf/bpf_lru_list.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.10","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/bpf_lru_list.c","kernel/bpf/bpf_lru_list.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5"},{"url":"https://git.kernel.org/stable/c/440a2fdbb40608d55a7b11f2be53592a3785131d"},{"url":"https://git.kernel.org/stable/c/89edbdfc5d0308cef57b71359331de5c4ddbf763"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T05:17:29.070Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.10","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.10","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.10","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}