{"id":"CVE-2026-74643","summary":"samples/damon/mtier: error out for zero quota goal target values","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsamples/damon/mtier: error out for zero quota goal target values\n\nPatch series \"mm/damon: avoid division by zero from damos_quota_score()\".\n\nDAMON_SAMPLE_MTIER and DAMON_LRU_SORT allow the user to trigger division\nby zero in damos_quota_score().  Avoid it by adding parameters validation\nchecks.\n\n\nThis patch (of 2):\n\ndamos_quota_score() can trigger division by zero if the target_value is\nzero.  DAMON_SAMPLE_MTIER lets users set the target_value via\nnode0_mem_{used,free}_bp parameters.  It doesn't guard zero value case,\nthough.  As a result, users can trigger division by zero.  Fix the issue\nby returning an error when the user tries to start DAMON with zero\nnode0_mem_{used,free}_bp parameter values.\n\nDAMON_SAMPLE_MTIER is just a sample module, but the consequence is quite\nbad.  Also the zero node0_mem_free_bp parameter might look like a\nreasonable setup to some users.  Hence, the issue might really happen in\nthe real world.\n\nOne reliable way to reproduce the issue is like below:\n\n    # cd /sys/module/damon_sample_mtier/parameters\n    # echo 4096 \u003e node0_start_addr\n    # echo 8192 \u003e node0_end_addr\n    # echo 8192 \u003e node1_start_addr\n    # echo 81920 \u003e node1_end_addr\n    # echo 0 \u003e node0_mem_free_bp\n    # echo Y \u003e enabled\n    # dmesg -w\n    [...]\n    [18792.235916] Oops: divide error: 0000 [#1] SMP NOPTI\n    [...]\n    [18792.242787] RIP: 0010:damos_quota_score+0x6f/0x480\n    [...]\n\nThis issue was discovered [1] by Sashiko.","modified":"2026-08-24T11:47:20.368296216Z","published":"2026-08-22T15:32:21.140Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74643.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/684f271210becd7b8c4088f06c442499e48a43a0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a16fd3ad9d89b05475864da97327870464611736"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e16b8d640ec99b28bc827560edcf9706e610c3aa"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74643.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74643"},{"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":"c5e67d40a10234541e220750297304df79aaedd0"},{"fixed":"e16b8d640ec99b28bc827560edcf9706e610c3aa"},{"fixed":"684f271210becd7b8c4088f06c442499e48a43a0"},{"fixed":"a16fd3ad9d89b05475864da97327870464611736"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74643.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.17.0"},{"fixed":"6.18.45"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74643.json"}}],"schema_version":"1.9.0"}