CVE-2026-74643

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> samples/damon/mtier: error out for zero quota goal target values<br /> <br /> Patch series "mm/damon: avoid division by zero from damos_quota_score()".<br /> <br /> DAMON_SAMPLE_MTIER and DAMON_LRU_SORT allow the user to trigger division<br /> by zero in damos_quota_score(). Avoid it by adding parameters validation<br /> checks.<br /> <br /> <br /> This patch (of 2):<br /> <br /> damos_quota_score() can trigger division by zero if the target_value is<br /> zero. DAMON_SAMPLE_MTIER lets users set the target_value via<br /> node0_mem_{used,free}_bp parameters. It doesn&amp;#39;t guard zero value case,<br /> though. As a result, users can trigger division by zero. Fix the issue<br /> by returning an error when the user tries to start DAMON with zero<br /> node0_mem_{used,free}_bp parameter values.<br /> <br /> DAMON_SAMPLE_MTIER is just a sample module, but the consequence is quite<br /> bad. Also the zero node0_mem_free_bp parameter might look like a<br /> reasonable setup to some users. Hence, the issue might really happen in<br /> the real world.<br /> <br /> One reliable way to reproduce the issue is like below:<br /> <br /> # cd /sys/module/damon_sample_mtier/parameters<br /> # echo 4096 &gt; node0_start_addr<br /> # echo 8192 &gt; node0_end_addr<br /> # echo 8192 &gt; node1_start_addr<br /> # echo 81920 &gt; node1_end_addr<br /> # echo 0 &gt; node0_mem_free_bp<br /> # echo Y &gt; enabled<br /> # dmesg -w<br /> [...]<br /> [18792.235916] Oops: divide error: 0000 [#1] SMP NOPTI<br /> [...]<br /> [18792.242787] RIP: 0010:damos_quota_score+0x6f/0x480<br /> [...]<br /> <br /> This issue was discovered [1] by Sashiko.