{"id":"CVE-2026-98166","aliases":[],"title":"drm/ttm: fix swapped-out resources never leaving their bulk_move range","titleSource":"Linux","descriptionSource":"Linux","products":[{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"060f8f3020516d71bc4d6159d4d0beef85606a74","status":"affected","lessThan":"b48ebe399b4e72baa323462580fdd83ebda561e1","versionType":"git"},{"version":"b2ed01e7ad3de80333e9b962a44024b094bc0b2b","status":"affected","lessThan":"1169fe8c11ca45e3f91d59a73eb271d0ca8a7fb0","versionType":"git"},{"version":"b2ed01e7ad3de80333e9b962a44024b094bc0b2b","status":"affected","lessThan":"3db7d7d583419f7b1f2e141e36418802dbb25cf8","versionType":"git"},{"version":"0124a09e3e5f5f6080efe9663b27af27933f8382","status":"affected","versionType":"git"},{"version":"6.18.57","status":"affected","lessThan":"6.18.59","versionType":"semver"},{"version":"7.0.10","status":"affected","lessThan":"7.1","versionType":"semver"}],"defaultStatus":"unaffected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-98166"},{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.8","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"defaultStatus":"affected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-98166"}],"remediation":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/ttm: fix swapped-out resources never leaving their bulk_move range\n\nttm_tt_swapout() returns the number of pages swapped out on success and\na negative error code on failure; for a populated ttm it never returns\nzero. Commit b2ed01e7ad3d (\"drm/ttm: Fix ttm_bo_swapout() infinite LRU\nwalk on swapout failure\") moved the bulk_move bookkeeping in\nttm_bo_swapout_cb() under \"if (!ret)\", so the\nttm_resource_del_bulk_move_unevictable() / ttm_resource_move_to_lru_tail()\npair is now skipped on every successful swapout. The equivalent change\nfor the shrinker in commit 1d59f36e95f7 (\"drm/ttm: Fix ttm_bo_shrink()\ninfinite LRU walk on backup failure\") tests \"lret > 0\", which is what\nwas intended here as well.\n\nBefore b2ed01e7ad3d the resource was taken off the bulk_move before the\nswapout; since then a swapped-out resource stays inside its BO's\nbulk_move range (and on the manager LRU) although it is unevictable.\nWhen it is later freed or the BO leaves the bulk_move\n(ttm_resource_free(), ttm_bo_set_bulk_move() via amdgpu_vm_bo_del()),\nttm_resource_del_bulk_move() skips it because of its\n!ttm_resource_unevictable() guard, so a range endpoint in pos->first /\npos->last is left pointing at freed memory. The next\nttm_lru_bulk_move_tail() or ttm_resource_add_bulk_move() on that cursor\nis a use-after-free, seen as the resv WARN in ttm_lru_bulk_move_add(),\n\"list_del corruption\" in ttm_resource_move_to_lru_tail() or a NULL\ndereference in ttm_resource_manager_next() -- minutes to hours after a\nhibernation, or at process exit / reboot following one. Samuel\nAinsworth's analysis of drm/amd issue 5387 (see Link) identified the\ndangling cursor; the missing removal at swapout time is the reason it\ndangles.\n\nTesting the condition for success restores the removal. On an AMD\nPhoenix APU (ASUS UM3406GA, gfx1103) running suspend-then-hibernate on\na 7.0.y stable kernel carrying the backport (Ubuntu 7.0.0-31) the bug\ncrashed 5 of 18 hibernation cycles; a function profile of one\nhibernation showed 336 ttm_tt_swapout() calls and zero\nttm_resource_del_bulk_move_unevictable() calls. With this change the\nremoval happens for every swapped-out resource and 12 further cycles\nwere clean.","severity":"high","score":7.8,"published":"2026-10-06T08:44:11.927Z","modified":"2026-10-26T15:12:59.824Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://git.kernel.org/stable/c/b48ebe399b4e72baa323462580fdd83ebda561e1","https://git.kernel.org/stable/c/1169fe8c11ca45e3f91d59a73eb271d0ca8a7fb0","https://git.kernel.org/stable/c/3db7d7d583419f7b1f2e141e36418802dbb25cf8"],"sources":[{"name":"CVE","id":"CVE-2026-98166","modified":"2026-10-26T15:12:59.824Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-98166"}],"assessments":[{"source":"Linux","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8}],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-29T02:15:32.063Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}