CVE-2026-64458

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mm/damon/ops-common: handle extreme intervals in damon_hot_score()<br /> <br /> Fix three issues in damon_hot_score() that comes from wrong handling of<br /> extreme (zero or too high) monitoring intervals user setup.<br /> <br /> When the user sets sampling interval zero, damon_max_nr_accesses(), which<br /> is called from damon_hot_score(), causes a divide-by-zero. Needless to<br /> say, it is a problem.<br /> <br /> When the user sets the aggregation interval zero, the function returns<br /> zero. It is wrong, since the real maximum nr_acceses in the setup should<br /> be one. Worse yet, it can cause another divide-by-zero from its caller,<br /> damon_hot_score(), since it uses damon_max_nr_accesses() return value as a<br /> denominator.<br /> <br /> When the user sets the aggregation interval very high, damon_hot_score()<br /> could return a value out of [0, DAMOS_MAX_SCORE] range. Since the return<br /> value is used as an index to the regions_score_histogram array, which is<br /> DAMOS_MAX_SCORE+1 size, it causes out of bounds array access.<br /> <br /> The issues can be relatively easily reproduced like below. The sysfs<br /> write permission is required, though.<br /> <br /> # ./damo start --damos_action lru_prio --damos_quota_space 100M \<br /> --damos_quota_interval 1s<br /> # cd /sys/kernel/mm/damon/admin/kdamonds/0<br /> # echo 0 &gt; contexts/0/monitoring_attrs/intervals/sample_us<br /> # echo 0 &gt; contexts/0/monitoring_attrs/intervals/aggr_us<br /> # echo commit &gt; state<br /> # dmesg<br /> [...]<br /> [ 131.329762] Oops: divide error: 0000 [#1] SMP NOPTI<br /> [...]<br /> [ 131.336089] RIP: 0010:damon_hot_score+0x27/0xd0<br /> [...]<br /> <br /> Fix the divide-by-zero intervals problems by explicitly handling the zero<br /> intervals in damon_max_nr_accesses(). Fix the out-of-bound array access<br /> by applying [0, DAMOS_MAX_SCORE] bounds before returning from<br /> damon_hot_score().<br /> <br /> The issue was discovered [1] by Sashiko.