FKIE_CVE-2026-23018
Vulnerability from fkie_nvd - Published: 2026-01-31 12:16 - Updated: 2026-03-25 18:02
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
btrfs: release path before initializing extent tree in btrfs_read_locked_inode()
In btrfs_read_locked_inode() we are calling btrfs_init_file_extent_tree()
while holding a path with a read locked leaf from a subvolume tree, and
btrfs_init_file_extent_tree() may do a GFP_KERNEL allocation, which can
trigger reclaim.
This can create a circular lock dependency which lockdep warns about with
the following splat:
[6.1433] ======================================================
[6.1574] WARNING: possible circular locking dependency detected
[6.1583] 6.18.0+ #4 Tainted: G U
[6.1591] ------------------------------------------------------
[6.1599] kswapd0/117 is trying to acquire lock:
[6.1606] ffff8d9b6333c5b8 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x39/0x2f0
[6.1625]
but task is already holding lock:
[6.1633] ffffffffa4ab8ce0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x195/0xc60
[6.1646]
which lock already depends on the new lock.
[6.1657]
the existing dependency chain (in reverse order) is:
[6.1667]
-> #2 (fs_reclaim){+.+.}-{0:0}:
[6.1677] fs_reclaim_acquire+0x9d/0xd0
[6.1685] __kmalloc_cache_noprof+0x59/0x750
[6.1694] btrfs_init_file_extent_tree+0x90/0x100
[6.1702] btrfs_read_locked_inode+0xc3/0x6b0
[6.1710] btrfs_iget+0xbb/0xf0
[6.1716] btrfs_lookup_dentry+0x3c5/0x8e0
[6.1724] btrfs_lookup+0x12/0x30
[6.1731] lookup_open.isra.0+0x1aa/0x6a0
[6.1739] path_openat+0x5f7/0xc60
[6.1746] do_filp_open+0xd6/0x180
[6.1753] do_sys_openat2+0x8b/0xe0
[6.1760] __x64_sys_openat+0x54/0xa0
[6.1768] do_syscall_64+0x97/0x3e0
[6.1776] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[6.1784]
-> #1 (btrfs-tree-00){++++}-{3:3}:
[6.1794] lock_release+0x127/0x2a0
[6.1801] up_read+0x1b/0x30
[6.1808] btrfs_search_slot+0x8e0/0xff0
[6.1817] btrfs_lookup_inode+0x52/0xd0
[6.1825] __btrfs_update_delayed_inode+0x73/0x520
[6.1833] btrfs_commit_inode_delayed_inode+0x11a/0x120
[6.1842] btrfs_log_inode+0x608/0x1aa0
[6.1849] btrfs_log_inode_parent+0x249/0xf80
[6.1857] btrfs_log_dentry_safe+0x3e/0x60
[6.1865] btrfs_sync_file+0x431/0x690
[6.1872] do_fsync+0x39/0x80
[6.1879] __x64_sys_fsync+0x13/0x20
[6.1887] do_syscall_64+0x97/0x3e0
[6.1894] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[6.1903]
-> #0 (&delayed_node->mutex){+.+.}-{3:3}:
[6.1913] __lock_acquire+0x15e9/0x2820
[6.1920] lock_acquire+0xc9/0x2d0
[6.1927] __mutex_lock+0xcc/0x10a0
[6.1934] __btrfs_release_delayed_node.part.0+0x39/0x2f0
[6.1944] btrfs_evict_inode+0x20b/0x4b0
[6.1952] evict+0x15a/0x2f0
[6.1958] prune_icache_sb+0x91/0xd0
[6.1966] super_cache_scan+0x150/0x1d0
[6.1974] do_shrink_slab+0x155/0x6f0
[6.1981] shrink_slab+0x48e/0x890
[6.1988] shrink_one+0x11a/0x1f0
[6.1995] shrink_node+0xbfd/0x1320
[6.1002] balance_pgdat+0x67f/0xc60
[6.1321] kswapd+0x1dc/0x3e0
[6.1643] kthread+0xff/0x240
[6.1965] ret_from_fork+0x223/0x280
[6.1287] ret_from_fork_asm+0x1a/0x30
[6.1616]
other info that might help us debug this:
[6.1561] Chain exists of:
&delayed_node->mutex --> btrfs-tree-00 --> fs_reclaim
[6.1503] Possible unsafe locking scenario:
[6.1110] CPU0 CPU1
[6.1411] ---- ----
[6.1707] lock(fs_reclaim);
[6.1998] lock(btrfs-tree-00);
[6.1291] lock(fs_reclaim);
[6.1581] lock(&del
---truncated---
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | 6.17 | |
| linux | linux_kernel | 6.19 | |
| linux | linux_kernel | 6.19 | |
| linux | linux_kernel | 6.19 | |
| linux | linux_kernel | 6.19 | |
| linux | linux_kernel | 6.19 | |
| linux | linux_kernel | 6.19 | |
| linux | linux_kernel | 6.19 | |
| linux | linux_kernel | 6.19 |
{
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"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: release path before initializing extent tree in btrfs_read_locked_inode()\n\nIn btrfs_read_locked_inode() we are calling btrfs_init_file_extent_tree()\nwhile holding a path with a read locked leaf from a subvolume tree, and\nbtrfs_init_file_extent_tree() may do a GFP_KERNEL allocation, which can\ntrigger reclaim.\n\nThis can create a circular lock dependency which lockdep warns about with\nthe following splat:\n\n [6.1433] ======================================================\n [6.1574] WARNING: possible circular locking dependency detected\n [6.1583] 6.18.0+ #4 Tainted: G U\n [6.1591] ------------------------------------------------------\n [6.1599] kswapd0/117 is trying to acquire lock:\n [6.1606] ffff8d9b6333c5b8 (\u0026delayed_node-\u003emutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x39/0x2f0\n [6.1625]\n but task is already holding lock:\n [6.1633] ffffffffa4ab8ce0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x195/0xc60\n [6.1646]\n which lock already depends on the new lock.\n\n [6.1657]\n the existing dependency chain (in reverse order) is:\n [6.1667]\n -\u003e #2 (fs_reclaim){+.+.}-{0:0}:\n [6.1677] fs_reclaim_acquire+0x9d/0xd0\n [6.1685] __kmalloc_cache_noprof+0x59/0x750\n [6.1694] btrfs_init_file_extent_tree+0x90/0x100\n [6.1702] btrfs_read_locked_inode+0xc3/0x6b0\n [6.1710] btrfs_iget+0xbb/0xf0\n [6.1716] btrfs_lookup_dentry+0x3c5/0x8e0\n [6.1724] btrfs_lookup+0x12/0x30\n [6.1731] lookup_open.isra.0+0x1aa/0x6a0\n [6.1739] path_openat+0x5f7/0xc60\n [6.1746] do_filp_open+0xd6/0x180\n [6.1753] do_sys_openat2+0x8b/0xe0\n [6.1760] __x64_sys_openat+0x54/0xa0\n [6.1768] do_syscall_64+0x97/0x3e0\n [6.1776] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n [6.1784]\n -\u003e #1 (btrfs-tree-00){++++}-{3:3}:\n [6.1794] lock_release+0x127/0x2a0\n [6.1801] up_read+0x1b/0x30\n [6.1808] btrfs_search_slot+0x8e0/0xff0\n [6.1817] btrfs_lookup_inode+0x52/0xd0\n [6.1825] __btrfs_update_delayed_inode+0x73/0x520\n [6.1833] btrfs_commit_inode_delayed_inode+0x11a/0x120\n [6.1842] btrfs_log_inode+0x608/0x1aa0\n [6.1849] btrfs_log_inode_parent+0x249/0xf80\n [6.1857] btrfs_log_dentry_safe+0x3e/0x60\n [6.1865] btrfs_sync_file+0x431/0x690\n [6.1872] do_fsync+0x39/0x80\n [6.1879] __x64_sys_fsync+0x13/0x20\n [6.1887] do_syscall_64+0x97/0x3e0\n [6.1894] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n [6.1903]\n -\u003e #0 (\u0026delayed_node-\u003emutex){+.+.}-{3:3}:\n [6.1913] __lock_acquire+0x15e9/0x2820\n [6.1920] lock_acquire+0xc9/0x2d0\n [6.1927] __mutex_lock+0xcc/0x10a0\n [6.1934] __btrfs_release_delayed_node.part.0+0x39/0x2f0\n [6.1944] btrfs_evict_inode+0x20b/0x4b0\n [6.1952] evict+0x15a/0x2f0\n [6.1958] prune_icache_sb+0x91/0xd0\n [6.1966] super_cache_scan+0x150/0x1d0\n [6.1974] do_shrink_slab+0x155/0x6f0\n [6.1981] shrink_slab+0x48e/0x890\n [6.1988] shrink_one+0x11a/0x1f0\n [6.1995] shrink_node+0xbfd/0x1320\n [6.1002] balance_pgdat+0x67f/0xc60\n [6.1321] kswapd+0x1dc/0x3e0\n [6.1643] kthread+0xff/0x240\n [6.1965] ret_from_fork+0x223/0x280\n [6.1287] ret_from_fork_asm+0x1a/0x30\n [6.1616]\n other info that might help us debug this:\n\n [6.1561] Chain exists of:\n \u0026delayed_node-\u003emutex --\u003e btrfs-tree-00 --\u003e fs_reclaim\n\n [6.1503] Possible unsafe locking scenario:\n\n [6.1110] CPU0 CPU1\n [6.1411] ---- ----\n [6.1707] lock(fs_reclaim);\n [6.1998] lock(btrfs-tree-00);\n [6.1291] lock(fs_reclaim);\n [6.1581] lock(\u0026del\n---truncated---"
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta: btrfs: liberar ruta antes de inicializar el \u00e1rbol de extensiones en btrfs_read_locked_inode() En btrfs_read_locked_inode() estamos llamando a btrfs_init_file_extent_tree() mientras mantenemos una ruta con una hoja bloqueada para lectura de un \u00e1rbol de subvolumen, y btrfs_init_file_extent_tree() puede realizar una asignaci\u00f3n GFP_KERNEL, lo que puede activar la recuperaci\u00f3n. Esto puede crear una dependencia de bloqueo circular sobre la cual lockdep advierte con el siguiente splat: [6.1433] [6.1574] WARNING: posible dependencia de bloqueo circular detectada [6.1583] 6.18.0+ #4 Tainted: G U [6.1591] [6.1599] kswapd0/117 est\u00e1 intentando adquirir el bloqueo: [6.1606] ffff8d9b6333c5b8 (\u0026amp;delayed_node-\u0026gt;mutex){+.+.}-{3:3}, en: __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1625] pero la tarea ya est\u00e1 manteniendo el bloqueo: [6.1633] ffffffffa4ab8ce0 (fs_reclaim){+.+.}-{0:0}, en: balance_pgdat+0x195/0xc60 [6.1646] cuyo bloqueo ya depende del nuevo bloqueo. [6.1657] la cadena de dependencia existente (en orden inverso) es: [6.1667] -\u0026gt; #2 (fs_reclaim){+.+.}-{0:0}: [6.1677] fs_reclaim_acquire+0x9d/0xd0 [6.1685] __kmalloc_cache_noprof+0x59/0x750 [6.1694] btrfs_init_file_extent_tree+0x90/0x100 [6.1702] btrfs_read_locked_inode+0xc3/0x6b0 [6.1710] btrfs_iget+0xbb/0xf0 [6.1716] btrfs_lookup_dentry+0x3c5/0x8e0 [6.1724] btrfs_lookup+0x12/0x30 [6.1731] lookup_open.isra.0+0x1aa/0x6a0 [6.1739] path_openat+0x5f7/0xc60 [6.1746] do_filp_open+0xd6/0x180 [6.1753] do_sys_openat2+0x8b/0xe0 [6.1760] __x64_sys_openat+0x54/0xa0 [6.1768] do_syscall_64+0x97/0x3e0 [6.1776] entry_SYSCALL_64_after_hwframe+0x76/0x7e [6.1784] -\u0026gt; #1 (btrfs-tree-00){++++}-{3:3}: [6.1794] lock_release+0x127/0x2a0 [6.1801] up_read+0x1b/0x30 [6.1808] btrfs_search_slot+0x8e0/0xff0 [6.1817] btrfs_lookup_inode+0x52/0xd0 [6.1825] __btrfs_update_delayed_inode+0x73/0x520 [6.1833] btrfs_commit_inode_delayed_inode+0x11a/0x120 [6.1842] btrfs_log_inode+0x608/0x1aa0 [6.1849] btrfs_log_inode_parent+0x249/0xf80 [6.1857] btrfs_log_dentry_safe+0x3e/0x60 [6.1865] btrfs_sync_file+0x431/0x690 [6.1872] do_fsync+0x39/0x80 [6.1879] __x64_sys_fsync+0x13/0x20 [6.1887] do_syscall_64+0x97/0x3e0 [6.1894] entry_SYSCALL_64_after_hwframe+0x76/0x7e [6.1903] -\u0026gt; #0 (\u0026amp;delayed_node-\u0026gt;mutex){+.+.}-{3:3}: [6.1913] __lock_acquire+0x15e9/0x2820 [6.1920] lock_acquire+0xc9/0x2d0 [6.1927] __mutex_lock+0xcc/0x10a0 [6.1934] __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1944] btrfs_evict_inode+0x20b/0x4b0 [6.1952] evict+0x15a/0x2f0 [6.1958] prune_icache_sb+0x91/0xd0 [6.1966] super_cache_scan+0x150/0x1d0 [6.1974] do_shrink_slab+0x155/0x6f0 [6.1981] shrink_slab+0x48e/0x890 [6.1988] shrink_one+0x11a/0x1f0 [6.1995] shrink_node+0xbfd/0x1320 [6.1002] balance_pgdat+0x67f/0xc60 [6.1321] kswapd+0x1dc/0x3e0 [6.1643] kthread+0xff/0x240 [6.1965] ret_from_fork+0x223/0x280 [6.1287] ret_from_fork_asm+0x1a/0x30 [6.1616] otra informaci\u00f3n que podr\u00eda ayudarnos a depurar esto: [6.1561] La cadena existe de: \u0026amp;delayed_node-\u0026gt;mutex --\u0026gt; btrfs-tree-00 --\u0026gt; fs_reclaim [6.1503] Posible escenario de bloqueo inseguro: [6.1110] CPU0 CPU1 [6.1411] [6.1707] lock(fs_reclaim); [6.1998] lock(btrfs-tree-00); [6.1291] lock(fs_reclaim); [6.1581] lock(\u0026amp;del ---truncado---"
}
],
"id": "CVE-2026-23018",
"lastModified": "2026-03-25T18:02:15.263",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
]
},
"published": "2026-01-31T12:16:05.100",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/8731f2c50b0b1d2b58ed5b9671ef2c4bdc2f8347"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/92a5590851144f034adc51fee55e6878ccac716e"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "NVD-CWE-noinfo"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- 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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