{"api_version":"1","generated_at":"2026-10-25T13:32:26+00:00","cve":"CVE-2026-98538","urls":{"html":"https://cve.report/CVE-2026-98538","api":"https://cve.report/api/cve/CVE-2026-98538.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98538","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98538"},"summary":{"title":"writeback: bound cleanup_offline_cgwb() rescans by rotating scanned inodes","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nwriteback: bound cleanup_offline_cgwb() rescans by rotating scanned inodes\n\ncleanup_offline_cgwb() prepares at most WB_MAX_INODES_PER_ISW inodes\nper call and is called again until the dying wb is drained, but every\ncall walks wb->b_attached and then wb->b_dirty_time from the same end.\nInodes already prepared (they stay on the list with I_WB_SWITCH set\nuntil the switch worker runs) and inodes that cannot be switched\n(I_FREEING, I_WILL_FREE, !SB_ACTIVE, DAX, already on the target wb)\nstay where they are, so each pass rescans a growing run of them under\nwb->list_lock and a full drain is quadratic in the number of inodes on\nthe list. With ~17M inodes attached to one dying cgwb we saw this end\nin soft lockups, with CPUs reported stuck for 21-48s.\n\nWalk both lists from the oldest end and move every scanned inode to\nthe newest end, so the next pass starts where the previous one stopped\nand the drain becomes linear. b_attached is unordered, so nobody sees\nthe reorder there. b_dirty_time is ordered by dirtied_when, but the\noldest unscanned inode stays at the end move_expired_inodes() picks\nfrom, sync takes the whole list regardless of order, and prepared\ninodes leave the list as soon as the switch work runs and get a new\ndirtied_time_when on the new wb anyway, so the only inodes left out of\norder are the ones that can never switch (DAX), and only on the dying\nwb.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-18 16:17:05","updated_at":"2026-10-18 16:17:05"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/2d1da58c79b66646721a644c6eb4dd1f9c5c9327","name":"https://git.kernel.org/stable/c/2d1da58c79b66646721a644c6eb4dd1f9c5c9327","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dd4b92067238771b604b59fdda8efed6d70ee823","name":"https://git.kernel.org/stable/c/dd4b92067238771b604b59fdda8efed6d70ee823","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/624dd0931162523d70f9db8c120b5ec6429a9b97","name":"https://git.kernel.org/stable/c/624dd0931162523d70f9db8c120b5ec6429a9b97","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9dac137bf77e0683778fb34c86e730c6129e8cb6","name":"https://git.kernel.org/stable/c/9dac137bf77e0683778fb34c86e730c6129e8cb6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c96b4d1628868e1195da1a896f79e06f350a3187","name":"https://git.kernel.org/stable/c/c96b4d1628868e1195da1a896f79e06f350a3187","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f6988c90671e83db79df1b7b9d6fdb0e5947fd84","name":"https://git.kernel.org/stable/c/f6988c90671e83db79df1b7b9d6fdb0e5947fd84","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98538","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98538","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c22d70a162d3cc177282c4487be4d54876ca55c8 2d1da58c79b66646721a644c6eb4dd1f9c5c9327 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c22d70a162d3cc177282c4487be4d54876ca55c8 c96b4d1628868e1195da1a896f79e06f350a3187 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c22d70a162d3cc177282c4487be4d54876ca55c8 624dd0931162523d70f9db8c120b5ec6429a9b97 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c22d70a162d3cc177282c4487be4d54876ca55c8 dd4b92067238771b604b59fdda8efed6d70ee823 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c22d70a162d3cc177282c4487be4d54876ca55c8 9dac137bf77e0683778fb34c86e730c6129e8cb6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c22d70a162d3cc177282c4487be4d54876ca55c8 f6988c90671e83db79df1b7b9d6fdb0e5947fd84 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.189 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.158 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.112 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.55 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.9 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/fs-writeback.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"2d1da58c79b66646721a644c6eb4dd1f9c5c9327","status":"affected","version":"c22d70a162d3cc177282c4487be4d54876ca55c8","versionType":"git"},{"lessThan":"c96b4d1628868e1195da1a896f79e06f350a3187","status":"affected","version":"c22d70a162d3cc177282c4487be4d54876ca55c8","versionType":"git"},{"lessThan":"624dd0931162523d70f9db8c120b5ec6429a9b97","status":"affected","version":"c22d70a162d3cc177282c4487be4d54876ca55c8","versionType":"git"},{"lessThan":"dd4b92067238771b604b59fdda8efed6d70ee823","status":"affected","version":"c22d70a162d3cc177282c4487be4d54876ca55c8","versionType":"git"},{"lessThan":"9dac137bf77e0683778fb34c86e730c6129e8cb6","status":"affected","version":"c22d70a162d3cc177282c4487be4d54876ca55c8","versionType":"git"},{"lessThan":"f6988c90671e83db79df1b7b9d6fdb0e5947fd84","status":"affected","version":"c22d70a162d3cc177282c4487be4d54876ca55c8","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/fs-writeback.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.14"},{"lessThan":"5.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.189","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.158","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.112","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.55","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.189","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.158","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.112","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.55","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.9","versionStartIncluding":"5.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"5.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nwriteback: bound cleanup_offline_cgwb() rescans by rotating scanned inodes\n\ncleanup_offline_cgwb() prepares at most WB_MAX_INODES_PER_ISW inodes\nper call and is called again until the dying wb is drained, but every\ncall walks wb->b_attached and then wb->b_dirty_time from the same end.\nInodes already prepared (they stay on the list with I_WB_SWITCH set\nuntil the switch worker runs) and inodes that cannot be switched\n(I_FREEING, I_WILL_FREE, !SB_ACTIVE, DAX, already on the target wb)\nstay where they are, so each pass rescans a growing run of them under\nwb->list_lock and a full drain is quadratic in the number of inodes on\nthe list. With ~17M inodes attached to one dying cgwb we saw this end\nin soft lockups, with CPUs reported stuck for 21-48s.\n\nWalk both lists from the oldest end and move every scanned inode to\nthe newest end, so the next pass starts where the previous one stopped\nand the drain becomes linear. b_attached is unordered, so nobody sees\nthe reorder there. b_dirty_time is ordered by dirtied_when, but the\noldest unscanned inode stays at the end move_expired_inodes() picks\nfrom, sync takes the whole list regardless of order, and prepared\ninodes leave the list as soon as the switch work runs and get a new\ndirtied_time_when on the new wb anyway, so the only inodes left out of\norder are the ones that can never switch (DAX), and only on the dying\nwb."}],"providerMetadata":{"dateUpdated":"2026-10-19T09:21:21.678Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/2d1da58c79b66646721a644c6eb4dd1f9c5c9327"},{"url":"https://git.kernel.org/stable/c/c96b4d1628868e1195da1a896f79e06f350a3187"},{"url":"https://git.kernel.org/stable/c/624dd0931162523d70f9db8c120b5ec6429a9b97"},{"url":"https://git.kernel.org/stable/c/dd4b92067238771b604b59fdda8efed6d70ee823"},{"url":"https://git.kernel.org/stable/c/9dac137bf77e0683778fb34c86e730c6129e8cb6"},{"url":"https://git.kernel.org/stable/c/f6988c90671e83db79df1b7b9d6fdb0e5947fd84"}],"title":"writeback: bound cleanup_offline_cgwb() rescans by rotating scanned inodes","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98538","datePublished":"2026-10-18T15:18:05.901Z","dateReserved":"2026-09-25T10:25:14.356Z","dateUpdated":"2026-10-19T09:21:21.678Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-18 16:17:05","lastModifiedDate":"2026-10-18 16:17:05","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98538","Ordinal":"1","Title":"writeback: bound cleanup_offline_cgwb() rescans by rotating scan","CVE":"CVE-2026-98538","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98538","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nwriteback: bound cleanup_offline_cgwb() rescans by rotating scanned inodes\n\ncleanup_offline_cgwb() prepares at most WB_MAX_INODES_PER_ISW inodes\nper call and is called again until the dying wb is drained, but every\ncall walks wb->b_attached and then wb->b_dirty_time from the same end.\nInodes already prepared (they stay on the list with I_WB_SWITCH set\nuntil the switch worker runs) and inodes that cannot be switched\n(I_FREEING, I_WILL_FREE, !SB_ACTIVE, DAX, already on the target wb)\nstay where they are, so each pass rescans a growing run of them under\nwb->list_lock and a full drain is quadratic in the number of inodes on\nthe list. With ~17M inodes attached to one dying cgwb we saw this end\nin soft lockups, with CPUs reported stuck for 21-48s.\n\nWalk both lists from the oldest end and move every scanned inode to\nthe newest end, so the next pass starts where the previous one stopped\nand the drain becomes linear. b_attached is unordered, so nobody sees\nthe reorder there. b_dirty_time is ordered by dirtied_when, but the\noldest unscanned inode stays at the end move_expired_inodes() picks\nfrom, sync takes the whole list regardless of order, and prepared\ninodes leave the list as soon as the switch work runs and get a new\ndirtied_time_when on the new wb anyway, so the only inodes left out of\norder are the ones that can never switch (DAX), and only on the dying\nwb.","Type":"Description","Title":"writeback: bound cleanup_offline_cgwb() rescans by rotating scan"}]}}}