FKIE_CVE-2026-23036
Vulnerability from fkie_nvd - Published: 2026-01-31 12:16 - Updated: 2026-06-17 10:20
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
btrfs: release path before iget_failed() in btrfs_read_locked_inode()
In btrfs_read_locked_inode() if we fail to lookup the inode, we jump to
the 'out' label with a path that has a read locked leaf and then we call
iget_failed(). This can result in a ABBA deadlock, since iget_failed()
triggers inode eviction and that causes the release of the delayed inode,
which must lock the delayed inode's mutex, and a task updating a delayed
inode starts by taking the node's mutex and then modifying the inode's
subvolume btree.
Syzbot reported the following lockdep splat for this:
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
btrfs-cleaner/8725 is trying to acquire lock:
ffff0000d6826a48 (&delayed_node->mutex){+.+.}-{4:4}, at: __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290
but task is already holding lock:
ffff0000dbeba878 (btrfs-tree-00){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x44/0x2ec fs/btrfs/locking.c:145
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (btrfs-tree-00){++++}-{4:4}:
__lock_release kernel/locking/lockdep.c:5574 [inline]
lock_release+0x198/0x39c kernel/locking/lockdep.c:5889
up_read+0x24/0x3c kernel/locking/rwsem.c:1632
btrfs_tree_read_unlock+0xdc/0x298 fs/btrfs/locking.c:169
btrfs_tree_unlock_rw fs/btrfs/locking.h:218 [inline]
btrfs_search_slot+0xa6c/0x223c fs/btrfs/ctree.c:2133
btrfs_lookup_inode+0xd8/0x38c fs/btrfs/inode-item.c:395
__btrfs_update_delayed_inode+0x124/0xed0 fs/btrfs/delayed-inode.c:1032
btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1118 [inline]
__btrfs_commit_inode_delayed_items+0x15f8/0x1748 fs/btrfs/delayed-inode.c:1141
__btrfs_run_delayed_items+0x1ac/0x514 fs/btrfs/delayed-inode.c:1176
btrfs_run_delayed_items_nr+0x28/0x38 fs/btrfs/delayed-inode.c:1219
flush_space+0x26c/0xb68 fs/btrfs/space-info.c:828
do_async_reclaim_metadata_space+0x110/0x364 fs/btrfs/space-info.c:1158
btrfs_async_reclaim_metadata_space+0x90/0xd8 fs/btrfs/space-info.c:1226
process_one_work+0x7e8/0x155c kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x958/0xed8 kernel/workqueue.c:3427
kthread+0x5fc/0x75c kernel/kthread.c:463
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
-> #0 (&delayed_node->mutex){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237
lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
__mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598
__mutex_lock kernel/locking/mutex.c:760 [inline]
mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812
__btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290
btrfs_release_delayed_node fs/btrfs/delayed-inode.c:315 [inline]
btrfs_remove_delayed_node+0x68/0x84 fs/btrfs/delayed-inode.c:1326
btrfs_evict_inode+0x578/0xe28 fs/btrfs/inode.c:5587
evict+0x414/0x928 fs/inode.c:810
iput_final fs/inode.c:1914 [inline]
iput+0x95c/0xad4 fs/inode.c:1966
iget_failed+0xec/0x134 fs/bad_inode.c:248
btrfs_read_locked_inode+0xe1c/0x1234 fs/btrfs/inode.c:4101
btrfs_iget+0x1b0/0x264 fs/btrfs/inode.c:5837
btrfs_run_defrag_inode fs/btrfs/defrag.c:237 [inline]
btrfs_run_defrag_inodes+0x520/0xdc4 fs/btrf
---truncated---
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/btrfs/inode.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "65241e3ddda60b53a4ee3ae12721fc9ee21d5827",
"status": "affected",
"version": "69673992b1aea5540199d9b8b658ede72f55a6cf",
"versionType": "git"
},
{
"lessThan": "1e1f2055ad5a7a5d548789b334a4473a7665c418",
"status": "affected",
"version": "69673992b1aea5540199d9b8b658ede72f55a6cf",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/btrfs/inode.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.13"
},
{
"lessThan": "6.13",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.7",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.19",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: release path before iget_failed() in btrfs_read_locked_inode()\n\nIn btrfs_read_locked_inode() if we fail to lookup the inode, we jump to\nthe \u0027out\u0027 label with a path that has a read locked leaf and then we call\niget_failed(). This can result in a ABBA deadlock, since iget_failed()\ntriggers inode eviction and that causes the release of the delayed inode,\nwhich must lock the delayed inode\u0027s mutex, and a task updating a delayed\ninode starts by taking the node\u0027s mutex and then modifying the inode\u0027s\nsubvolume btree.\n\nSyzbot reported the following lockdep splat for this:\n\n ======================================================\n WARNING: possible circular locking dependency detected\n syzkaller #0 Not tainted\n ------------------------------------------------------\n btrfs-cleaner/8725 is trying to acquire lock:\n ffff0000d6826a48 (\u0026delayed_node-\u003emutex){+.+.}-{4:4}, at: __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290\n\n but task is already holding lock:\n ffff0000dbeba878 (btrfs-tree-00){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x44/0x2ec fs/btrfs/locking.c:145\n\n which lock already depends on the new lock.\n\n the existing dependency chain (in reverse order) is:\n\n -\u003e #1 (btrfs-tree-00){++++}-{4:4}:\n __lock_release kernel/locking/lockdep.c:5574 [inline]\n lock_release+0x198/0x39c kernel/locking/lockdep.c:5889\n up_read+0x24/0x3c kernel/locking/rwsem.c:1632\n btrfs_tree_read_unlock+0xdc/0x298 fs/btrfs/locking.c:169\n btrfs_tree_unlock_rw fs/btrfs/locking.h:218 [inline]\n btrfs_search_slot+0xa6c/0x223c fs/btrfs/ctree.c:2133\n btrfs_lookup_inode+0xd8/0x38c fs/btrfs/inode-item.c:395\n __btrfs_update_delayed_inode+0x124/0xed0 fs/btrfs/delayed-inode.c:1032\n btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1118 [inline]\n __btrfs_commit_inode_delayed_items+0x15f8/0x1748 fs/btrfs/delayed-inode.c:1141\n __btrfs_run_delayed_items+0x1ac/0x514 fs/btrfs/delayed-inode.c:1176\n btrfs_run_delayed_items_nr+0x28/0x38 fs/btrfs/delayed-inode.c:1219\n flush_space+0x26c/0xb68 fs/btrfs/space-info.c:828\n do_async_reclaim_metadata_space+0x110/0x364 fs/btrfs/space-info.c:1158\n btrfs_async_reclaim_metadata_space+0x90/0xd8 fs/btrfs/space-info.c:1226\n process_one_work+0x7e8/0x155c kernel/workqueue.c:3263\n process_scheduled_works kernel/workqueue.c:3346 [inline]\n worker_thread+0x958/0xed8 kernel/workqueue.c:3427\n kthread+0x5fc/0x75c kernel/kthread.c:463\n ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844\n\n -\u003e #0 (\u0026delayed_node-\u003emutex){+.+.}-{4:4}:\n check_prev_add kernel/locking/lockdep.c:3165 [inline]\n check_prevs_add kernel/locking/lockdep.c:3284 [inline]\n validate_chain kernel/locking/lockdep.c:3908 [inline]\n __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237\n lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868\n __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598\n __mutex_lock kernel/locking/mutex.c:760 [inline]\n mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812\n __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290\n btrfs_release_delayed_node fs/btrfs/delayed-inode.c:315 [inline]\n btrfs_remove_delayed_node+0x68/0x84 fs/btrfs/delayed-inode.c:1326\n btrfs_evict_inode+0x578/0xe28 fs/btrfs/inode.c:5587\n evict+0x414/0x928 fs/inode.c:810\n iput_final fs/inode.c:1914 [inline]\n iput+0x95c/0xad4 fs/inode.c:1966\n iget_failed+0xec/0x134 fs/bad_inode.c:248\n btrfs_read_locked_inode+0xe1c/0x1234 fs/btrfs/inode.c:4101\n btrfs_iget+0x1b0/0x264 fs/btrfs/inode.c:5837\n btrfs_run_defrag_inode fs/btrfs/defrag.c:237 [inline]\n btrfs_run_defrag_inodes+0x520/0xdc4 fs/btrf\n---truncated---"
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta: btrfs: liberar la ruta antes de iget_failed() en btrfs_read_locked_inode() En btrfs_read_locked_inode() si no logramos buscar el inodo, saltamos a la etiqueta \u0027out\u0027 con una ruta que tiene una hoja bloqueada para lectura y luego llamamos a iget_failed(). Esto puede resultar en un interbloqueo ABBA, ya que iget_failed() activa el desalojo del inodo y eso causa la liberaci\u00f3n del inodo retrasado, el cual debe bloquear el mutex del inodo retrasado, y una tarea que actualiza un inodo retrasado comienza tomando el mutex del nodo y luego modificando el btree del subvolumen del inodo. Syzbot inform\u00f3 el siguiente splat de lockdep para esto: ADVERTENCIA: posible dependencia de bloqueo circular detectada syzkaller #0 No contaminado btrfs-cleaner/8725 est\u00e1 intentando adquirir el bloqueo: ffff0000d6826a48 (\u0026amp;delayed_node-\u0026gt;mutex){+.+.}-{4:4}, en: __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290 pero la tarea ya tiene el bloqueo: ffff0000dbeba878 (btrfs-tree-00){++++}-{4:4}, en: btrfs_tree_read_lock_nested+0x44/0x2ec fs/btrfs/locking.c:145 cuyo bloqueo ya depende del nuevo bloqueo. la cadena de dependencia existente (en orden inverso) es: -\u0026gt; #1 (btrfs-tree-00){++++}-{4:4}: __lock_release kernel/locking/lockdep.c:5574 [en l\u00ednea] lock_release+0x198/0x39c kernel/locking/lockdep.c:5889 up_read+0x24/0x3c kernel/locking/rwsem.c:1632 btrfs_tree_read_unlock+0xdc/0x298 fs/btrfs/locking.c:169 btrfs_tree_unlock_rw fs/btrfs/locking.h:218 [en l\u00ednea] btrfs_search_slot+0xa6c/0x223c fs/btrfs/ctree.c:2133 btrfs_lookup_inode+0xd8/0x38c fs/btrfs/inode-item.c:395 __btrfs_update_delayed_inode+0x124/0xed0 fs/btrfs/delayed-inode.c:1032 btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1118 [en l\u00ednea] __btrfs_commit_inode_delayed_items+0x15f8/0x1748 fs/btrfs/delayed-inode.c:1141 __btrfs_run_delayed_items+0x1ac/0x514 fs/btrfs/delayed-inode.c:1176 btrfs_run_delayed_items_nr+0x28/0x38 fs/btrfs/delayed-inode.c:1219 flush_space+0x26c/0xb68 fs/btrfs/space-info.c:828 do_async_reclaim_metadata_space+0x110/0x364 fs/btrfs/space-info.c:1158 btrfs_async_reclaim_metadata_space+0x90/0xd8 fs/btrfs/space-info.c:1226 process_one_work+0x7e8/0x155c kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [en l\u00ednea] worker_thread+0x958/0xed8 kernel/workqueue.c:3427 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 -\u0026gt; #0 (\u0026amp;delayed_node-\u0026gt;mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [en l\u00ednea] check_prevs_add kernel/locking/lockdep.c:3284 [en l\u00ednea] validate_chain kernel/locking/lockdep.c:3908 [en l\u00ednea] __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868 __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598 __mutex_lock kernel/locking/mutex.c:760 [en l\u00ednea] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812 __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290 btrfs_release_delayed_node fs/btrfs/delayed-inode.c:315 [en l\u00ednea] btrfs_remove_delayed_node+0x68/0x84 fs/btrfs/delayed-inode.c:1326 btrfs_evict_inode+0x578/0xe28 fs/btrfs/inode.c:5587 evict+0x414/0x928 fs/inode.c:810 iput_final fs/inode.c:1914 [en l\u00ednea] iput+0x95c/0xad4 fs/inode.c:1966 iget_failed+0xec/0x134 fs/bad_inode.c:248 btrfs_read_locked_inode+0xe1c/0x1234 fs/btrfs/inode.c:4101 btrfs_iget+0x1b0/0x264 fs/btrfs/inode.c:5837 trfs_run_defrag_inode fs/btrfs/defrag.c:237 [en l\u00ednea] btrfs_run_defrag_inodes+0x520/0xdc4 fs/btrf ---truncado---"
}
],
"id": "CVE-2026-23036",
"lastModified": "2026-06-17T10:20:45.143",
"metrics": {},
"published": "2026-01-31T12:16:06.910",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/1e1f2055ad5a7a5d548789b334a4473a7665c418"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/65241e3ddda60b53a4ee3ae12721fc9ee21d5827"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Deferred"
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
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- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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