ext4: clear stale xarray tags on folios skipped during writeback

{
  "id": "281b028d3fed9c659457194f83a87487f3a71dc66f0d4a38169488d613fe53fa",
  "url": "https://osv.dev/vulnerability/CVE-2026-92502",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ext4: clear stale xarray tags on folios skipped during writeback",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ext4: clear stale xarray tags on folios skipped during writeback In data=journal mode, the writeback thread can hit the WARN_ON_ONCE(sb_rdonly(sb)) in ext4_journal_check_start() while the superblock is being remounted read-only during reboot: Workqueue: writeback wb_workfn (flush-253:0) RIP: 0010:ext4_journal_check_start+0x8b/0xd0 Call Trace: __ext4_journal_start_sb+0x3c/0x1e0 mpage_prepare_extent_to_map+0x4af/0x580 ext4_do_writepages+0x3c0/0x1080 ext4_writepages+0xc8/0x1a0 do_writepages+0xc4/0x180 __writeback_single_inode+0x45/0x2f0 writeback_sb_inodes+0x26b/0x5d0 __writeback_inodes_wb+0x54/0x100 wb_writeback+0x1ac/0x320 wb_workfn+0x394/0x470 And followed by the warning: EXT4-fs warning (device vda1): ext4_evict_inode:195: inode #6263: comm (sd-umount): data will be lost This issue is not reproduced every time, but frequently. The reproduction step is to create a VM with 8 CPUs, 16G memory and setup data=journal: sudo tune2fs -o journal_data /dev/vda1 Run fio: rm -f fiotest fio --name=fiotest --rw=randwrite --bs=4k --runtime=6 --ioengine=libaio --iodepth=256 --numjobs=8 --filename=fiotest --filesize=30G --group_reporting Reboot the VM, and check the console output from: virsh console testvm But there is no dirty inode, folio_clear_dirty_for_io clears PG_dirty but leaves tags PAGECACHE_TAG_DIRTY and PAGECACHE_TAG_TOWRITE set which are only cleared by __folio_start_writeback. In data=journal mode, jbd2 checkpo",
    "evidence": "osv:CVE-2026-92502",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.110",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.52",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-92502",
      "aliases": [
        "CVE-2026-92502"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "dff4ac75eeeefc4397fe7cf8ce559425bf46b1f7"
                },
                {
                  "fixed": "f82a4929d0ef7ddf254c1c295ec1dfd24094f2de"
                },
                {
                  "fixed": "a450ab88bfd57b227d72c7a3faad54d16c3fc099"
                },
                {
                  "fixed": "aa0042630b1f7cab735b0a168539281198822586"
                },
                {
                  "fixed": "43ae387c3ae6a11227d096669ddf883e27a39a11"
                },
                {
                  "fixed": "ec524aae479b4b2078c47492b90ec21200bce434"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-92502.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.157"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.110"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.52"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-92502.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.420449163Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/43ae387c3ae6a11227d096669ddf883e27a39a11",
        "https://git.kernel.org/stable/c/a450ab88bfd57b227d72c7a3faad54d16c3fc099",
        "https://git.kernel.org/stable/c/aa0042630b1f7cab735b0a168539281198822586",
        "https://git.kernel.org/stable/c/ec524aae479b4b2078c47492b90ec21200bce434",
        "https://git.kernel.org/stable/c/f82a4929d0ef7ddf254c1c295ec1dfd24094f2de",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/92xxx/CVE-2026-92502.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-92502",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/92xxx/CVE-2026-92502.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-92502",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 499654,
  "published_at": "2026-09-17T16:10:15.399+00:00"
}