{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "c22d70a162d3cc177282c4487be4d54876ca55c8"
            },
            {
              "fixed": "2d1da58c79b66646721a644c6eb4dd1f9c5c9327"
            },
            {
              "fixed": "c96b4d1628868e1195da1a896f79e06f350a3187"
            },
            {
              "fixed": "624dd0931162523d70f9db8c120b5ec6429a9b97"
            },
            {
              "fixed": "dd4b92067238771b604b59fdda8efed6d70ee823"
            },
            {
              "fixed": "9dac137bf77e0683778fb34c86e730c6129e8cb6"
            },
            {
              "fixed": "f6988c90671e83db79df1b7b9d6fdb0e5947fd84"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.14.0"
            },
            {
              "fixed": "6.1.189"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.158"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.112"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.55"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98538.json"
  },
  "details": "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-\u003eb_attached and then wb-\u003eb_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-\u003elist_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.",
  "id": "CVE-2026-98538",
  "modified": "2026-10-20T02:30:47.833545779Z",
  "published": "2026-10-18T15:18:05.901Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2d1da58c79b66646721a644c6eb4dd1f9c5c9327"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/624dd0931162523d70f9db8c120b5ec6429a9b97"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9dac137bf77e0683778fb34c86e730c6129e8cb6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c96b4d1628868e1195da1a896f79e06f350a3187"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dd4b92067238771b604b59fdda8efed6d70ee823"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f6988c90671e83db79df1b7b9d6fdb0e5947fd84"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98538.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98538"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "writeback: bound cleanup_offline_cgwb() rescans by rotating scanned inodes"
}