{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2025-22115", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-22115", "idYear": 2025, "status": "PUBLISHED", "publishedAt": "2025-04-16T14:13:01.293Z", "updatedAt": "2026-10-21T12:36:17.108Z", "importedAt": "2026-10-24T01:57:29.455Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "btrfs: fix block group refcount race in btrfs_create_pending_block_groups()", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix block group refcount race in btrfs_create_pending_block_groups()\n\nBlock group creation is done in two phases, which results in a slightly\nunintuitive property: a block group can be allocated/deallocated from\nafter btrfs_make_block_group() adds it to the space_info with\nbtrfs_add_bg_to_space_info(), but before creation is completely completed\nin btrfs_create_pending_block_groups(). As a result, it is possible for a\nblock group to go unused and have 'btrfs_mark_bg_unused' called on it\nconcurrently with 'btrfs_create_pending_block_groups'. This causes a\nnumber of issues, which were fixed with the block group flag\n'BLOCK_GROUP_FLAG_NEW'.\n\nHowever, this fix is not quite complete. Since it does not use the\nunused_bg_lock, it is possible for the following race to occur:\n\nbtrfs_create_pending_block_groups btrfs_mark_bg_unused\n if list_empty // false\n list_del_init\n clear_bit\n else if (test_bit) // true\n list_move_tail\n\nAnd we get into the exact same broken ref count and invalid new_bgs\nstate for transaction cleanup that BLOCK_GROUP_FLAG_NEW was designed to\nprevent.\n\nThe broken refcount aspect will result in a warning like:\n\n [1272.943527] refcount_t: underflow; use-after-free.\n [1272.943967] WARNING: CPU: 1 PID: 61 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x110\n [1272.944731] Modules linked in: btrfs virtio_net xor zstd_compress raid6_pq null_blk [last unloaded: btrfs]\n [1272.945550] CPU: 1 UID: 0 PID: 61 Comm: kworker/u32:1 Kdump: loaded Tainted: G W 6.14.0-rc5+ #108\n [1272.946368] Tainted: [W]=WARN\n [1272.946585] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014\n [1272.947273] Workqueue: btrfs_discard btrfs_discard_workfn [btrfs]\n [1272.947788] RIP: 0010:refcount_warn_saturate+0xba/0x110\n [1272.949532] RSP: 0018:ffffbf1200247df0 EFLAGS: 00010282\n [1272.949901] RAX: 0000000000000000 RBX: ffffa14b00e3f800 RCX: 0000000000000000\n [1272.950437] RDX: 0000000000000000 RSI: ffffbf1200247c78 RDI: 00000000ffffdfff\n [1272.950986] RBP: ffffa14b00dc2860 R08: 00000000ffffdfff R09: ffffffff90526268\n [1272.951512] R10: ffffffff904762c0 R11: 0000000063666572 R12: ffffa14b00dc28c0\n [1272.952024] R13: 0000000000000000 R14: ffffa14b00dc2868 R15: 000001285dcd12c0\n [1272.952850] FS: 0000000000000000(0000) GS:ffffa14d33c40000(0000) knlGS:0000000000000000\n [1272.953458] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n [1272.953931] CR2: 00007f838cbda000 CR3: 000000010104e000 CR4: 00000000000006f0\n [1272.954474] Call Trace:\n [1272.954655] \n [1272.954812] ? refcount_warn_saturate+0xba/0x110\n [1272.955173] ? __warn.cold+0x93/0xd7\n [1272.955487] ? refcount_warn_saturate+0xba/0x110\n [1272.955816] ? report_bug+0xe7/0x120\n [1272.956103] ? handle_bug+0x53/0x90\n [1272.956424] ? exc_invalid_op+0x13/0x60\n [1272.956700] ? asm_exc_invalid_op+0x16/0x20\n [1272.957011] ? refcount_warn_saturate+0xba/0x110\n [1272.957399] btrfs_discard_cancel_work.cold+0x26/0x2b [btrfs]\n [1272.957853] btrfs_put_block_group.cold+0x5d/0x8e [btrfs]\n [1272.958289] btrfs_discard_workfn+0x194/0x380 [btrfs]\n [1272.958729] process_one_work+0x130/0x290\n [1272.959026] worker_thread+0x2ea/0x420\n [1272.959335] ? __pfx_worker_thread+0x10/0x10\n [1272.959644] kthread+0xd7/0x1c0\n [1272.959872] ? __pfx_kthread+0x10/0x10\n [1272.960172] ret_from_fork+0x30/0x50\n [1272.960474] ? __pfx_kthread+0x10/0x10\n [1272.960745] ret_from_fork_asm+0x1a/0x30\n [1272.961035] \n [1272.961238] ---[ end trace 0000000000000000 ]---\n\nThough we have seen them in the async discard workfn as well. It is\nmost likely to happen after a relocation finishes which cancels discard,\ntears down the block group, etc.\n\nFix this fully by taking the lock arou\n---truncated---", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "0657b20c5a76c938612f8409735a8830d257866e", "status": "affected", "versionType": "git", "lessThan": "77fd40b7ed0c3acf989a0f2a07b15a0a59ea8f96" }, { "version": "0657b20c5a76c938612f8409735a8830d257866e", "status": "affected", "versionType": "git", "lessThan": "ee56da95f8962b86fec4ef93f866e64c8d025a58" }, { "version": "0657b20c5a76c938612f8409735a8830d257866e", "status": "affected", "versionType": "git", "lessThan": "9d383a6fc59271aaaf07a33b23b2eac5b9268b7a" }, { "version": "0657b20c5a76c938612f8409735a8830d257866e", "status": "affected", "versionType": "git", "lessThan": "2d8e5168d48a91e7a802d3003e72afb4304bebfa" }, { "version": "6297644db23f77c02ae7961cc542d162629ae2c4", "status": "affected", "versionType": "git" }, { "version": "7569c4294ba6ff9f194635b14876198f8a687c4a", "status": "affected", "versionType": "git" }, { "version": "6.1.47", "status": "affected", "versionType": "semver", "lessThan": "6.2" }, { "version": "6.4.12", "status": "affected", "versionType": "semver", "lessThan": "6.5" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "6.5", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "6.5" }, { "version": "6.6.160", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.40", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.14.2", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.14.*" }, { "version": "6.15", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }