{ "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-2021-47637", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-47637", "idYear": 2021, "status": "PUBLISHED", "publishedAt": "2025-02-26T01:54:10.709Z", "updatedAt": "2026-05-11T13:58:14.868Z", "importedAt": "2026-10-24T01:56:36.661Z", "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": "ubifs: Fix deadlock in concurrent rename whiteout and inode writeback", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nubifs: Fix deadlock in concurrent rename whiteout and inode writeback\n\nFollowing hung tasks:\n[ 77.028764] task:kworker/u8:4 state:D stack: 0 pid: 132\n[ 77.028820] Call Trace:\n[ 77.029027] schedule+0x8c/0x1b0\n[ 77.029067] mutex_lock+0x50/0x60\n[ 77.029074] ubifs_write_inode+0x68/0x1f0 [ubifs]\n[ 77.029117] __writeback_single_inode+0x43c/0x570\n[ 77.029128] writeback_sb_inodes+0x259/0x740\n[ 77.029148] wb_writeback+0x107/0x4d0\n[ 77.029163] wb_workfn+0x162/0x7b0\n\n[ 92.390442] task:aa state:D stack: 0 pid: 1506\n[ 92.390448] Call Trace:\n[ 92.390458] schedule+0x8c/0x1b0\n[ 92.390461] wb_wait_for_completion+0x82/0xd0\n[ 92.390469] __writeback_inodes_sb_nr+0xb2/0x110\n[ 92.390472] writeback_inodes_sb_nr+0x14/0x20\n[ 92.390476] ubifs_budget_space+0x705/0xdd0 [ubifs]\n[ 92.390503] do_rename.cold+0x7f/0x187 [ubifs]\n[ 92.390549] ubifs_rename+0x8b/0x180 [ubifs]\n[ 92.390571] vfs_rename+0xdb2/0x1170\n[ 92.390580] do_renameat2+0x554/0x770\n\n, are caused by concurrent rename whiteout and inode writeback processes:\n\trename_whiteout(Thread 1)\t wb_workfn(Thread2)\nubifs_rename\n do_rename\n lock_4_inodes (Hold ui_mutex)\n ubifs_budget_space\n make_free_space\n shrink_liability\n\t __writeback_inodes_sb_nr\n\t bdi_split_work_to_wbs (Queue new wb work)\n\t\t\t\t\t wb_do_writeback(wb work)\n\t\t\t\t\t\t__writeback_single_inode\n\t\t\t\t\t ubifs_write_inode\n\t\t\t\t\t LOCK(ui_mutex)\n\t\t\t\t\t\t\t ↑\n\t wb_wait_for_completion (Wait wb work) <-- deadlock!\n\nReproducer (Detail program in [Link]):\n 1. SYS_renameat2(\"/mp/dir/file\", \"/mp/dir/whiteout\", RENAME_WHITEOUT)\n 2. Consume out of space before kernel(mdelay) doing budget for whiteout\n\nFix it by doing whiteout space budget before locking ubifs inodes.\nBTW, it also fixes wrong goto tag 'out_release' in whiteout budget\nerror handling path(It should at least recover dir i_size and unlock\n4 ubifs inodes).", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798", "status": "affected", "versionType": "git", "lessThan": "9dddc8211430fb851ddf0b168e3a00c6f66cc185" }, { "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798", "status": "affected", "versionType": "git", "lessThan": "37bdf1ad592555ecda1d55b89f6e393e4c0589d1" }, { "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798", "status": "affected", "versionType": "git", "lessThan": "83e42a78428fc354f5e2049935b84c8d8d29b787" }, { "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798", "status": "affected", "versionType": "git", "lessThan": "c58af8564a7b08757173009030b74baf4b2b762b" }, { "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798", "status": "affected", "versionType": "git", "lessThan": "70e9090acc32348cedc5def0cd6d5c126efc97b9" }, { "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798", "status": "affected", "versionType": "git", "lessThan": "8b278c8dcfb565cb65eceb62a38cbf7a7c326db5" }, { "version": "9e0a1fff8db56eaaebb74b4a3ef65f86811c4798", "status": "affected", "versionType": "git", "lessThan": "afd427048047e8efdedab30e8888044e2be5aa9c" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "4.9", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "4.9" }, { "version": "4.19.238", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "4.19.*" }, { "version": "5.4.189", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.4.*" }, { "version": "5.10.110", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.33", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "5.16.19", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.16.*" }, { "version": "5.17.2", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.17.*" }, { "version": "5.18", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }