GHSA-V7CW-956X-792R
Vulnerability from github – Published: 2026-01-31 12:30 – Updated: 2026-01-31 12:30In 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---
{
"affected": [],
"aliases": [
"CVE-2026-23036"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-01-31T12:16:06Z",
"severity": null
},
"details": "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---",
"id": "GHSA-v7cw-956x-792r",
"modified": "2026-01-31T12:30:12Z",
"published": "2026-01-31T12:30:12Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23036"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1e1f2055ad5a7a5d548789b334a4473a7665c418"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/65241e3ddda60b53a4ee3ae12721fc9ee21d5827"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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