{"id":"CVE-2026-98398","state":"PUBLISHED","title":"locking/lockdep: Invalidate stale class_cache entries for zapped classes","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nlocking/lockdep: Invalidate stale class_cache entries for zapped classes\n\nsyzbot reported a lockdep splat hitting DEBUG_LOCKS_WARN_ON(1) in\nhlock_class() due to an invalid class_idx:\n\n  WARNING: kernel/locking/lockdep.c:238 at __lock_acquire+0x382/0x2cf0 kernel/locking/lockdep.c:5203\n  Workqueue: wg-crypt-wg0 wg_packet_tx_worker\n  RIP: 0010:hlock_class kernel/locking/lockdep.c:238 [inline]\n  RIP: 0010:check_wait_context kernel/locking/lockdep.c:4870 [inline]\n  RIP: 0010:__lock_acquire+0x389/0x2cf0 kernel/locking/lockdep.c:5203\n  Call Trace:\n   <IRQ>\n   lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5886\n   _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173\n   tcp_tsq_handler+0x29/0x200 net/ipv4/tcp_output.c:1291\n   tcp_tsq_workfn+0x384/0x410 net/ipv4/tcp_output.c:1325\n   ...\n\nWhen a lock class is zapped (e.g. during module unload or key\nunregistration), zap_class() clears the class's bit in\nlock_classes_in_use and removes it from the class hash table.\nHowever, existing lockdep_map instances embedded in data structures\nmay still retain a pointer to the zapped class in their class_cache[]\narray.\n\nWhen __lock_acquire() subsequently runs on such a lock, it finds\nlock->class_cache[subclass] != NULL, skipping register_lock_class()\nand assigning hlock->class_idx to the index of the zapped class. When\ncheck_wait_context() or hlock_class() inspects the held_lock, it finds\n!test_bit(class_idx, lock_classes_in_use) and warns. Furthermore, if\nthe zapped slot is subsequently re-allocated to an unrelated lock key,\nthe stale class_cache entry would erroneously match the unrelated\nclass (ABA issue).\n\nAdd lock_class_cache_is_valid() to validate that the cached class is\nwithin lock_classes bounds, still allocated in lock_classes_in_use\n(using uninstrumented arch_test_bit() in __always_inline context so it\nis safe in noinstr contexts like match_held_lock()), and that\nclass->key matches the expected subkey (taking lockdep_set_subclass()\noverrides into account). Also use READ_ONCE()/WRITE_ONCE() when\naccessing class_cache[].  If the entry is invalid or stale, fall back\nto register_lock_class() / look_up_lock_class().","publishedAt":"2026-10-14T13:25:59.676Z","updatedAt":"2026-10-19T09:18:51.739Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"f8a1281ab82df5b51fd0384354d4b21daf2b7af0","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"1c9d664e2e067fca69e5a41d68e23bbc66a583fe","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"6bc345f6d81ebe22e0f355c2a21d7e29691f9332","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"f63c86e9d267629758adaba18579e784ddd63c32","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"c7acfb04c7e2e2dea248282b21373d93296644dd","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"baa320fbb2f9fea50f5632a307da8ce84fbef5bd","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"02c6be7d675b21d81f0ba3a524346850a8c0e3bf","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/locking/lockdep.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.1","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/locking/lockdep.c"]}],"references":["https://git.kernel.org/stable/c/f8a1281ab82df5b51fd0384354d4b21daf2b7af0","https://git.kernel.org/stable/c/1c9d664e2e067fca69e5a41d68e23bbc66a583fe","https://git.kernel.org/stable/c/6bc345f6d81ebe22e0f355c2a21d7e29691f9332","https://git.kernel.org/stable/c/f63c86e9d267629758adaba18579e784ddd63c32","https://git.kernel.org/stable/c/c7acfb04c7e2e2dea248282b21373d93296644dd","https://git.kernel.org/stable/c/baa320fbb2f9fea50f5632a307da8ce84fbef5bd","https://git.kernel.org/stable/c/02c6be7d675b21d81f0ba3a524346850a8c0e3bf"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98398.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98398","state":"PUBLISHED","datePublished":"2026-10-14T13:25:59.676Z","dateUpdated":"2026-10-19T09:18:51.739Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.346Z"},"containers":{"cna":{"title":"locking/lockdep: Invalidate stale class_cache entries for zapped classes","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nlocking/lockdep: Invalidate stale class_cache entries for zapped classes\n\nsyzbot reported a lockdep splat hitting DEBUG_LOCKS_WARN_ON(1) in\nhlock_class() due to an invalid class_idx:\n\n  WARNING: kernel/locking/lockdep.c:238 at __lock_acquire+0x382/0x2cf0 kernel/locking/lockdep.c:5203\n  Workqueue: wg-crypt-wg0 wg_packet_tx_worker\n  RIP: 0010:hlock_class kernel/locking/lockdep.c:238 [inline]\n  RIP: 0010:check_wait_context kernel/locking/lockdep.c:4870 [inline]\n  RIP: 0010:__lock_acquire+0x389/0x2cf0 kernel/locking/lockdep.c:5203\n  Call Trace:\n   <IRQ>\n   lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5886\n   _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173\n   tcp_tsq_handler+0x29/0x200 net/ipv4/tcp_output.c:1291\n   tcp_tsq_workfn+0x384/0x410 net/ipv4/tcp_output.c:1325\n   ...\n\nWhen a lock class is zapped (e.g. during module unload or key\nunregistration), zap_class() clears the class's bit in\nlock_classes_in_use and removes it from the class hash table.\nHowever, existing lockdep_map instances embedded in data structures\nmay still retain a pointer to the zapped class in their class_cache[]\narray.\n\nWhen __lock_acquire() subsequently runs on such a lock, it finds\nlock->class_cache[subclass] != NULL, skipping register_lock_class()\nand assigning hlock->class_idx to the index of the zapped class. When\ncheck_wait_context() or hlock_class() inspects the held_lock, it finds\n!test_bit(class_idx, lock_classes_in_use) and warns. Furthermore, if\nthe zapped slot is subsequently re-allocated to an unrelated lock key,\nthe stale class_cache entry would erroneously match the unrelated\nclass (ABA issue).\n\nAdd lock_class_cache_is_valid() to validate that the cached class is\nwithin lock_classes bounds, still allocated in lock_classes_in_use\n(using uninstrumented arch_test_bit() in __always_inline context so it\nis safe in noinstr contexts like match_held_lock()), and that\nclass->key matches the expected subkey (taking lockdep_set_subclass()\noverrides into account). Also use READ_ONCE()/WRITE_ONCE() when\naccessing class_cache[].  If the entry is invalid or stale, fall back\nto register_lock_class() / look_up_lock_class()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"f8a1281ab82df5b51fd0384354d4b21daf2b7af0","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"1c9d664e2e067fca69e5a41d68e23bbc66a583fe","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"6bc345f6d81ebe22e0f355c2a21d7e29691f9332","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"f63c86e9d267629758adaba18579e784ddd63c32","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"c7acfb04c7e2e2dea248282b21373d93296644dd","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"baa320fbb2f9fea50f5632a307da8ce84fbef5bd","versionType":"git"},{"version":"a0b0fd53e1e67639b303b15939b9c653dbe7a8c4","status":"affected","lessThan":"02c6be7d675b21d81f0ba3a524346850a8c0e3bf","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/locking/lockdep.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.1","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/locking/lockdep.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/f8a1281ab82df5b51fd0384354d4b21daf2b7af0"},{"url":"https://git.kernel.org/stable/c/1c9d664e2e067fca69e5a41d68e23bbc66a583fe"},{"url":"https://git.kernel.org/stable/c/6bc345f6d81ebe22e0f355c2a21d7e29691f9332"},{"url":"https://git.kernel.org/stable/c/f63c86e9d267629758adaba18579e784ddd63c32"},{"url":"https://git.kernel.org/stable/c/c7acfb04c7e2e2dea248282b21373d93296644dd"},{"url":"https://git.kernel.org/stable/c/baa320fbb2f9fea50f5632a307da8ce84fbef5bd"},{"url":"https://git.kernel.org/stable/c/02c6be7d675b21d81f0ba3a524346850a8c0e3bf"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:18:51.739Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"7.2.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.1","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}