{"id":"CVE-2026-74645","summary":"mm/damon/lru_sort: error out for \u003e10000 active_mem_bp","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/lru_sort: error out for \u003e10000 active_mem_bp\n\ndamos_quota_score() can trigger division by zero if the target value is\nzero.  DAMON_LRU_SORT lets users set the target value for the hot memory\nscheme via active_mem_bp parameter.  It avoids setting it as the target\nvalue if the parameter value is zero.  However, it also sets the cold\nmemory scheme with a target value that is calculated as '10000 -\nactive_mem_bp + 2'.  Hence, if a user sets active_mem_bp 10002, the cold\nmemory scheme's quota goal target value can be zero.  As a result,\ndivision by zero can be triggered.  Fix by returning an error when the\nuser tries to start DAMON with \u003e10000 active_mem_bp parameter value.\n\nIt makes no sense to set active_mem_bp with 10002.  It also requires\nmodule parameters write permission to reproduce the issue.  That said, the\nconsequence is quite bad.\n\nOne reliable way to reproduce the issue is like below:\n\n    # cd /sys/module/damon_lru_sort/parameters\n    # echo 1000 \u003e wmarks_high\n    # echo 995 \u003e wmarks_mid\n    # echo 0 \u003e wmarks_low\n    # echo 10002 \u003e active_mem_bp\n    # echo Y \u003e enabled\n    # dmesg -w\n    [...]\n    [  597.421247] Oops: divide error: 0000 [#1] SMP NOPTI\n    [  597.428848] RIP: 0010:damos_quota_score+0x6f/0x480\n\nThis issue was discovered [1] by Sashiko.","modified":"2026-08-24T11:47:18.930315660Z","published":"2026-08-22T15:32:22.645Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74645.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/06befa61c427e74319781e6f35a364cfc32dbae8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e7e5e5e0dfe2ea171044c24c263efae4ee882b3f"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74645.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74645"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"40d98d31cd7060228e03303c5c34ae7101020416"},{"fixed":"e7e5e5e0dfe2ea171044c24c263efae4ee882b3f"},{"fixed":"06befa61c427e74319781e6f35a364cfc32dbae8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74645.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0"},{"fixed":"7.1.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74645.json"}}],"schema_version":"1.9.0"}