{"id":"CVE-2025-21907","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-21907","generatedAt":"2026-10-28T04:45:47.533Z","title":"In the Linux kernel, the following vulnerability has been resolved: mm: memory-failure: update ttu flag inside unmap_poisoned_folio Patch series \"mm: memory_failure: unmap poisoned folio during migrate properly\", v3.","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: memory-failure: update ttu flag inside unmap_poisoned_folio\n\nPatch series \"mm: memory_failure: unmap poisoned folio during migrate\nproperly\", v3.\n\nFix two bugs during folio migration if the folio is poisoned.\n\n\nThis patch (of 3):\n\nCommit 6da6b1d4a7df (\"mm/hwpoison: convert TTU_IGNORE_HWPOISON to\nTTU_HWPOISON\") introduce TTU_HWPOISON to replace TTU_IGNORE_HWPOISON in\norder to stop send SIGBUS signal when accessing an error page after a\nmemory error on a clean folio.  However during page migration, anon folio\nmust be set with TTU_HWPOISON during unmap_*().  For pagecache we need\nsome policy just like the one in hwpoison_user_mappings to set this flag. \nSo move this policy from hwpoison_user_mappings to unmap_poisoned_folio to\nhandle this warning properly.\n\nWarning will be produced during unamp poison folio with the following log:\n\n  ------------[ cut here ]------------\n  WARNING: CPU: 1 PID: 365 at mm/rmap.c:1847 try_to_unmap_one+0x8fc/0xd3c\n  Modules linked in:\n  CPU: 1 UID: 0 PID: 365 Comm: bash Tainted: G        W          6.13.0-rc1-00018-gacdb4bbda7ab #42\n  Tainted: [W]=WARN\n  Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015\n  pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n  pc : try_to_unmap_one+0x8fc/0xd3c\n  lr : try_to_unmap_one+0x3dc/0xd3c\n  Call trace:\n   try_to_unmap_one+0x8fc/0xd3c (P)\n   try_to_unmap_one+0x3dc/0xd3c (L)\n   rmap_walk_anon+0xdc/0x1f8\n   rmap_walk+0x3c/0x58\n   try_to_unmap+0x88/0x90\n   unmap_poisoned_folio+0x30/0xa8\n   do_migrate_range+0x4a0/0x568\n   offline_pages+0x5a4/0x670\n   memory_block_action+0x17c/0x374\n   memory_subsys_offline+0x3c/0x78\n   device_offline+0xa4/0xd0\n   state_store+0x8c/0xf0\n   dev_attr_store+0x18/0x2c\n   sysfs_kf_write+0x44/0x54\n   kernfs_fop_write_iter+0x118/0x1a8\n   vfs_write+0x3a8/0x4bc\n   ksys_write+0x6c/0xf8\n   __arm64_sys_write+0x1c/0x28\n   invoke_syscall+0x44/0x100\n   el0_svc_common.constprop.0+0x40/0xe0\n   do_el0_svc+0x1c/0x28\n   el0_svc+0x30/0xd0\n   el0t_64_sync_handler+0xc8/0xcc\n   el0t_64_sync+0x198/0x19c\n  ---[ end trace 0000000000000000 ]---\n\n[mawupeng1@huawei.com: unmap_poisoned_folio(): remove shadowed local `mapping', per Miaohe]","published":"2025-04-01T16:15:21.000Z","lastModified":"2026-06-17T08:44:35.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["linux/linux kernel"],"epss":{"score":0.00203,"percentile":0.10206,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.20%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/425c12c076e6fc6b2cb04b9f960319d31dcabc76","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/608cc7deb428f1122ed426060233622ebf667b6e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b81679b1633aa43c0d973adfa816d78c1ed0d032","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-21907","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}