{"id":"CVE-2026-99240","published":"2026-11-02T16:17:49.773","lastModified":"2026-11-02T16:17:49.773","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/core: error damos_commit_quota_goal() for zero target_value\n\nPatch series \"mm/damon: move zero damos quota target_value handling to the\ncore layer\".\n\nHaving zero DAMOS quota target value can cause division by zero.  DAMON\nAPI callers are checking the target value parameters to avoid that.  It is\neasy to make mistakes in some of the multiple API callers.  Move that to\nthe core layer.\n\nPatch 1 adds the corner case handling into the core layer DAMON parameters\nvalidation logic.  Patches 2 and 3 remove no more needed DAMON API callers\nside handling of the corner case in DAMON_LRU_SORT and DMON_SAMPLIE_MTIER,\nrespectively.\n\n\nThis patch (of 3):\n\nIf a DAMOS scheme has a damos_quota_goal of zero target_value,\ndamos_quota_goal() could trigger division-by-zero error.  Hence each DAMON\nAPI callers should do the zero target_value validation.  It is easy to\nmake mistakes.  Actually such bugs in DAMON_LRU_SORT and\nDAMON_SAMPLE_MTIER were found and fixed [1].\n\nIt is better to handle the corner case only once in the core layer,\ninstead of multiple places in all DAMON API callers.  One straightforward\noption is using an alternative denominator for the corner case in the\ndamos_quota_goal().  However, the zero target_value is meaningless.  In\nthis case, the quota goal is always evaluated as achieved or\nover-achieved.  The quota will only keep being reduced.\n\nSimply avoid using zero target_value by adding a check in the core layer\nDAMOS quota goal parameters validation/commit path,\ndamos_commit_quota_goal().  Update it to return an error in the case. \nAlso update its caller to propagate the error.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/156aeda4d74e9007b56492ed1f3b5838822632be","tags":[]},{"url":"https://git.kernel.org/stable/c/cc190c4073f570fd78a9d00dd3d13a71eced5403","tags":[]},{"url":"https://git.kernel.org/stable/c/d5482be6243b816730689099c017109eb8730dd5","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}