{ "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-2024-57975", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2024-57975", "idYear": 2024, "status": "PUBLISHED", "publishedAt": "2025-02-27T02:07:03.586Z", "updatedAt": "2026-10-21T12:35:46.066Z", "importedAt": "2026-10-24T01:57:20.494Z", "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: do proper folio cleanup when run_delalloc_nocow() failed", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: do proper folio cleanup when run_delalloc_nocow() failed\n\n[BUG]\nWith CONFIG_DEBUG_VM set, test case generic/476 has some chance to crash\nwith the following VM_BUG_ON_FOLIO():\n\n BTRFS error (device dm-3): cow_file_range failed, start 1146880 end 1253375 len 106496 ret -28\n BTRFS error (device dm-3): run_delalloc_nocow failed, start 1146880 end 1253375 len 106496 ret -28\n page: refcount:4 mapcount:0 mapping:00000000592787cc index:0x12 pfn:0x10664\n aops:btrfs_aops [btrfs] ino:101 dentry name(?):\"f1774\"\n flags: 0x2fffff80004028(uptodate|lru|private|node=0|zone=2|lastcpupid=0xfffff)\n page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio))\n ------------[ cut here ]------------\n kernel BUG at mm/page-writeback.c:2992!\n Internal error: Oops - BUG: 00000000f2000800 [#1] SMP\n CPU: 2 UID: 0 PID: 3943513 Comm: kworker/u24:15 Tainted: G OE 6.12.0-rc7-custom+ #87\n Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE\n Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022\n Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs]\n pc : folio_clear_dirty_for_io+0x128/0x258\n lr : folio_clear_dirty_for_io+0x128/0x258\n Call trace:\n folio_clear_dirty_for_io+0x128/0x258\n btrfs_folio_clamp_clear_dirty+0x80/0xd0 [btrfs]\n __process_folios_contig+0x154/0x268 [btrfs]\n extent_clear_unlock_delalloc+0x5c/0x80 [btrfs]\n run_delalloc_nocow+0x5f8/0x760 [btrfs]\n btrfs_run_delalloc_range+0xa8/0x220 [btrfs]\n writepage_delalloc+0x230/0x4c8 [btrfs]\n extent_writepage+0xb8/0x358 [btrfs]\n extent_write_cache_pages+0x21c/0x4e8 [btrfs]\n btrfs_writepages+0x94/0x150 [btrfs]\n do_writepages+0x74/0x190\n filemap_fdatawrite_wbc+0x88/0xc8\n start_delalloc_inodes+0x178/0x3a8 [btrfs]\n btrfs_start_delalloc_roots+0x174/0x280 [btrfs]\n shrink_delalloc+0x114/0x280 [btrfs]\n flush_space+0x250/0x2f8 [btrfs]\n btrfs_async_reclaim_data_space+0x180/0x228 [btrfs]\n process_one_work+0x164/0x408\n worker_thread+0x25c/0x388\n kthread+0x100/0x118\n ret_from_fork+0x10/0x20\n Code: 910a8021 a90363f7 a9046bf9 94012379 (d4210000)\n ---[ end trace 0000000000000000 ]---\n\n[CAUSE]\nThe first two lines of extra debug messages show the problem is caused\nby the error handling of run_delalloc_nocow().\n\nE.g. we have the following dirtied range (4K blocksize 4K page size):\n\n 0 16K 32K\n |//////////////////////////////////////|\n | Pre-allocated |\n\nAnd the range [0, 16K) has a preallocated extent.\n\n- Enter run_delalloc_nocow() for range [0, 16K)\n Which found range [0, 16K) is preallocated, can do the proper NOCOW\n write.\n\n- Enter fallback_to_fow() for range [16K, 32K)\n Since the range [16K, 32K) is not backed by preallocated extent, we\n have to go COW.\n\n- cow_file_range() failed for range [16K, 32K)\n So cow_file_range() will do the clean up by clearing folio dirty,\n unlock the folios.\n\n Now the folios in range [16K, 32K) is unlocked.\n\n- Enter extent_clear_unlock_delalloc() from run_delalloc_nocow()\n Which is called with PAGE_START_WRITEBACK to start page writeback.\n But folios can only be marked writeback when it's properly locked,\n thus this triggered the VM_BUG_ON_FOLIO().\n\nFurthermore there is another hidden but common bug that\nrun_delalloc_nocow() is not clearing the folio dirty flags in its error\nhandling path.\nThis is the common bug shared between run_delalloc_nocow() and\ncow_file_range().\n\n[FIX]\n- Clear folio dirty for range [@start, @cur_offset)\n Introduce a helper, cleanup_dirty_folios(), which\n will find and lock the folio in the range, clear the dirty flag and\n start/end the writeback, with the extra handling for the\n @locked_folio.\n\n- Introduce a helper to clear folio dirty, start and end writeback\n\n- Introduce a helper to record the last failed COW range end\n This is to trace which range we should skip, to avoid double\n unlocking.\n\n- Skip the failed COW range for the e\n---truncated---", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "17ca04aff7e6171df684b7b65804df8830eb8c15", "status": "affected", "versionType": "git", "lessThan": "545d6893d3a34737d000af103e1557c592075c41" }, { "version": "17ca04aff7e6171df684b7b65804df8830eb8c15", "status": "affected", "versionType": "git", "lessThan": "5ae72abbf91eb172ce3a838a4dc34be3c9707296" }, { "version": "17ca04aff7e6171df684b7b65804df8830eb8c15", "status": "affected", "versionType": "git", "lessThan": "2434533f1c963e7317c45880c98287e5bed98325" }, { "version": "17ca04aff7e6171df684b7b65804df8830eb8c15", "status": "affected", "versionType": "git", "lessThan": "c2b47df81c8e20a8e8cd94f0d7df211137ae94ed" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "3.5", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "3.5" }, { "version": "6.6.160", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.13", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.13.2", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.13.*" }, { "version": "6.14", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }