{"id":"CVE-2026-92502","revision":null,"records":[{"revision":"5e064d74e0d64dbcbaa54433a14cf74d","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-92502","aliases":[],"title":"ext4: clear stale xarray tags on folios skipped during writeback","description":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: clear stale xarray tags on folios skipped during writeback\n\nIn data=journal mode, the writeback thread can hit the\nWARN_ON_ONCE(sb_rdonly(sb)) in ext4_journal_check_start() while the\nsuperblock is being remounted read-only during reboot:\n\nWorkqueue: writeback wb_workfn (flush-253:0)\nRIP: 0010:ext4_journal_check_start+0x8b/0xd0\nCall Trace:\n __ext4_journal_start_sb+0x3c/0x1e0\n mpage_prepare_extent_to_map+0x4af/0x580\n ext4_do_writepages+0x3c0/0x1080\n ext4_writepages+0xc8/0x1a0\n do_writepages+0xc4/0x180\n __writeback_single_inode+0x45/0x2f0\n writeback_sb_inodes+0x26b/0x5d0\n __writeback_inodes_wb+0x54/0x100\n wb_writeback+0x1ac/0x320\n wb_workfn+0x394/0x470\n\nAnd followed by the warning:\nEXT4-fs warning (device vda1): ext4_evict_inode:195: inode #6263:\ncomm (sd-umount): data will be lost\n\nThis issue is not reproduced every time, but frequently.\nThe reproduction step is to create a VM with 8 CPUs, 16G memory and\nsetup data=journal:\nsudo tune2fs -o journal_data /dev/vda1\nRun fio:\nrm -f fiotest\nfio --name=fiotest --rw=randwrite --bs=4k --runtime=6 --ioengine=libaio\n--iodepth=256 --numjobs=8 --filename=fiotest --filesize=30G\n--group_reporting\nReboot the VM, and check the console output from:\nvirsh console testvm\n\nBut there is no dirty inode, folio_clear_dirty_for_io clears PG_dirty\nbut leaves tags PAGECACHE_TAG_DIRTY and PAGECACHE_TAG_TOWRITE set which\nare only cleared by __folio_start_writeback.\nIn data=journal mode, jbd2 checkpoints the journalled data to its final\nlocation and clears its own dirty flag without touching folio PG_dirty\nor xarray dirty flags.\nThe commit f4a2b42e7891 (\"ext4: fix stale xarray tags after writeback\")\nfixes when PG_dirty is still set but there is no dirty page.\nAnother case is PG_dirty is cleared, but PAGECACHE_TAG_DIRTY and\nPAGECACHE_TAG_TOWRITE is still set. In this case, writeback thread\nchecks clean folio and skips it in mpage_prepare_extent_to_map:\nif (!folio_test_dirty(folio) ||\n ...\n folio_unlcok(folio);\n\tcontinue\n\nAnd never reaches ext4_bio_write_folio where the commit f4a2b42e7891\nclears the stale xarray tags. Print debug logs after the filesystem\nis remounted read-only:\nwritepages RDONLY nrpages=2048 dirtytag=1 wbtag=0 towrite=1 sync=0\nAnd all folios are actually clean:\nfolio idx=3 dirty=0 wb=0 checked=0 dirtybuf=0 jbddirty=0 mapped=1\n...\n\nWe need to clear the xarray stale tags for such clean folios by\ncycling them through writeback in the skip path, the same way\nf4a2b42e7891 does in ext4_bio_write_folio.","state":0,"publishedAt":"2026-09-17T16:10:15.399+00:00","modifiedAt":"2026-10-19T09:04:08.456+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"fs/ext4/inode.c\"\n ],\n \"versions\": [\n {\n \"version\": \"dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7\",\n \"lessThan\": \"f82a4929d0ef7ddf254c1c295ec1dfd24094f2de\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7\",\n \"lessThan\": \"a450ab88bfd57b227d72c7a3faad54d16c3fc099\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7\",\n \"lessThan\": \"aa0042630b1f7cab735b0a168539281198822586\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7\",\n \"lessThan\": \"43ae387c3ae6a11227d096669ddf883e27a39a11\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7\",\n \"lessThan\": \"ec524aae479b4b2078c47492b90ec21200bce434\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"fs/ext4/inode.c\"\n ],\n \"versions\": [\n {\n \"version\": \"6.2\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"6.2\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.157\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.110\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.52\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2.6\",\n \"lessThanOrEqual\": \"7.2.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.3\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/f82a4929d0ef7ddf254c1c295ec1dfd24094f2de","https://git.kernel.org/stable/c/a450ab88bfd57b227d72c7a3faad54d16c3fc099","https://git.kernel.org/stable/c/aa0042630b1f7cab735b0a168539281198822586","https://git.kernel.org/stable/c/43ae387c3ae6a11227d096669ddf883e27a39a11","https://git.kernel.org/stable/c/ec524aae479b4b2078c47492b90ec21200bce434"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-92502","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-92502","identifiers":["CVE-2026-92502"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-3c8e547b28ad4f0fa34b0d9a3442b37e","complete":false,"records":13654,"lastAttemptAt":"2026-11-09T02:21:06.332251+00:00","lastSuccessAt":"2026-11-09T02:21:06.328+00:00","error":null,"lastVerifiedAt":"2026-11-09T02:21:06.328+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13634,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. 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No reader inventory is sent.","generation":"enrichment-5a44a451442747cb81d83104fe1e7771","complete":true,"records":13666,"lastAttemptAt":"2026-11-09T02:08:52.2785198+00:00","lastSuccessAt":"2026-11-09T02:08:52.274+00:00","error":null,"lastVerifiedAt":"2026-11-09T02:08:52.274+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-980593e6977a6d1b4fb1eed5a1ffe88a468736f89f0a06f710924ad59132c023","complete":true,"records":9914,"lastAttemptAt":"2026-11-09T02:08:49.2635464+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-09T02:08:49.2635464+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-fde804134ecdda0ddd5ff5c26ee1fff5a6fa659311f7ef2e51c6ad54964db0e2","complete":true,"records":1971,"lastAttemptAt":"2026-11-09T02:08:48.7750517+00:00","lastSuccessAt":"2026-11-06T19:03:17.0399903+00:00","error":null,"lastVerifiedAt":"2026-11-09T02:08:48.7750517+00:00","snapshotPublishedAt":"2026-11-06T18:17:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-3b1150af6d7ada2c07356cbab4ead5224c1485027890f71c71d0742cddf0b9e8","complete":true,"records":3055,"lastAttemptAt":"2026-11-09T02:08:49.6317268+00:00","lastSuccessAt":"2026-11-09T00:02:23.4330288+00:00","error":null,"lastVerifiedAt":"2026-11-09T02:08:49.6317268+00:00","snapshotPublishedAt":"2026-11-08T23:17:54+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-f8647d7ba64b1ba0dfdc7130944766d5b36d5b77d18fff0c79e651a4cff3c2b9","complete":true,"records":231293,"lastAttemptAt":"2026-11-09T02:08:49.149268+00:00","lastSuccessAt":"2026-11-08T11:06:56.2918717+00:00","error":null,"lastVerifiedAt":"2026-11-09T02:08:49.149268+00:00","snapshotPublishedAt":"2026-11-08T11:02:50+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}