CVE-2026-23018 - Vulnerability Details

Vendors	Products
Linux	Linux Kernel

Link	Providers
https://git.kernel.org/stable/c/8731f2c50b0b1d2b58ed5b9671ef2c4bdc2f8347
https://git.kernel.org/stable/c/92a5590851144f034adc51fee55e6878ccac716e

Type	Values Removed	Values Added
Description		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---
Title		btrfs: release path before initializing extent tree in btrfs_read_locked_inode()
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/8731f2c50b0b1d2b58ed5b9671ef2c4bdc2f8347 https://git.kernel.org/stable/c/92a5590851144f034adc51fee55e6878ccac716e

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-23018", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.940Z", "datePublished": "2026-01-31T11:39:02.330Z", "dateUpdated": "2026-01-31T11:39:02.330Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-01-31T11:39:02.330Z"}, "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 (&delayed_node->mutex){+.+.}-{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 -> #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 -> #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 -> #0 (&delayed_node->mutex){+.+.}-{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 &delayed_node->mutex --> btrfs-tree-00 --> 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(&del\n---truncated---"}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/btrfs/inode.c"], "versions": [{"version": "8679d2687c351824d08cf1f0e86f3b65f22a00fe", "lessThan": "92a5590851144f034adc51fee55e6878ccac716e", "status": "affected", "versionType": "git"}, {"version": "8679d2687c351824d08cf1f0e86f3b65f22a00fe", "lessThan": "8731f2c50b0b1d2b58ed5b9671ef2c4bdc2f8347", "status": "affected", "versionType": "git"}, {"version": "e8f496001e0c7832d188ab91fea294e19a128202", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/btrfs/inode.c"], "versions": [{"version": "6.17", "status": "affected"}, {"version": "0", "lessThan": "6.17", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.6", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19-rc5", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17", "versionEndExcluding": "6.18.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17", "versionEndExcluding": "6.19-rc5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16.9"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/92a5590851144f034adc51fee55e6878ccac716e"}, {"url": "https://git.kernel.org/stable/c/8731f2c50b0b1d2b58ed5b9671ef2c4bdc2f8347"}], "title": "btrfs: release path before initializing extent tree in btrfs_read_locked_inode()", "x_generator": {"engine": "bippy-1.2.0"}}}}

{"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 (&delayed_node->mutex){+.+.}-{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 -> #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 -> #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 -> #0 (&delayed_node->mutex){+.+.}-{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 &delayed_node->mutex --> btrfs-tree-00 --> 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(&del\n---truncated---"}], "id": "CVE-2026-23018", "lastModified": "2026-01-31T12:16:05.100", "metrics": {}, "published": "2026-01-31T12:16:05.100", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8731f2c50b0b1d2b58ed5b9671ef2c4bdc2f8347"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/92a5590851144f034adc51fee55e6878ccac716e"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

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