CVE-2026-98398
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: locking/lockdep: Invalidate stale class_cache entries for zapped classes syzbot reported a lockdep splat hitting DEBUG_LOCKS_WARN_ON(1) in hlock_class() due to an invalid class_idx: WARNING: kernel/locking/lockdep.c:238 at __lock_acquire+0x382/0x2cf0 kernel/locking/lockdep.c:5203 Workqueue: wg-crypt-wg0 wg_packet_tx_worker RIP: 0010:hlock_class kernel/locking/lockdep.c:238 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4870 [inline] RIP: 0010:__lock_acquire+0x389/0x2cf0 kernel/locking/lockdep.c:5203 Call Trace: <IRQ> lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5886 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173 tcp_tsq_handler+0x29/0x200 net/ipv4/tcp_output.c:1291 tcp_tsq_workfn+0x384/0x410 net/ipv4/tcp_output.c:1325 ... When a lock class is zapped (e.g. during module unload or key unregistration), zap_class() clears the class's bit in lock_classes_in_use and removes it from the class hash table. However, existing lockdep_map instances embedded in data structures may still retain a pointer to the zapped class in their class_cache[] array. When __lock_acquire() subsequently runs on such a lock, it finds lock->class_cache[subclass] != NULL, skipping register_lock_class() and assigning hlock->class_idx to the index of the zapped class. When check_wait_context() or hlock_class() inspects the held_lock, it finds !test_bit(class_idx, lock_classes_in_use) and warns. Furthermore, if the zapped slot is subsequently re-allocated to an unrelated lock key, the stale class_cache entry would erroneously match the unrelated class (ABA issue). Add lock_class_cache_is_valid() to validate that the cached class is within lock_classes bounds, still allocated in lock_classes_in_use (using uninstrumented arch_test_bit() in __always_inline context so it is safe in noinstr contexts like match_held_lock()), and that class->key matches the expected subkey (taking lockdep_set_subclass() overrides into account). Also use READ_ONCE()/WRITE_ONCE() when accessing class_cache[]. If the entry is invalid or stale, fall back to register_lock_class() / look_up_lock_class().
View original CVE JSON
{
"id": "CVE-2026-98398",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-10-14T14:17:50.760",
"lastModified": "2026-10-19T10:18:44.480",
"vulnStatus": "Received",
"cveTags": [],
"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": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"kernel/locking/lockdep.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "a0b0fd53e1e67639b303b15939b9c653dbe7a8c4",
"lessThan": "f8a1281ab82df5b51fd0384354d4b21daf2b7af0",
"versionType": "git",
"status": "affected"
},
{
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"lessThan": "1c9d664e2e067fca69e5a41d68e23bbc66a583fe",
"versionType": "git",
"status": "affected"
},
{
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"versionType": "git",
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{
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"versionType": "git",
"status": "affected"
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{
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"versionType": "git",
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]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"kernel/locking/lockdep.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "5.1",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.1",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.15.222",
"lessThanOrEqual": "5.15.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.189",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.158",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.111",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.53",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.7",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/02c6be7d675b21d81f0ba3a524346850a8c0e3bf",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/1c9d664e2e067fca69e5a41d68e23bbc66a583fe",
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{
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
"url": "https://git.kernel.org/stable/c/f63c86e9d267629758adaba18579e784ddd63c32",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
"url": "https://git.kernel.org/stable/c/f8a1281ab82df5b51fd0384354d4b21daf2b7af0",
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}
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}