mm/damon/lru_sort: error out for >10000 active_mem_bp

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74645
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-22 16:16:37 UTC
Updated2026-08-22 16:16:37 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: mm/damon/lru_sort: error out for >10000 active_mem_bp damos_quota_score() can trigger division by zero if the target value is zero. DAMON_LRU_SORT lets users set the target value for the hot memory scheme via active_mem_bp parameter. It avoids setting it as the target value if the parameter value is zero. However, it also sets the cold memory scheme with a target value that is calculated as '10000 - active_mem_bp + 2'. Hence, if a user sets active_mem_bp 10002, the cold memory scheme's quota goal target value can be zero. As a result, division by zero can be triggered. Fix by returning an error when the user tries to start DAMON with >10000 active_mem_bp parameter value. It makes no sense to set active_mem_bp with 10002. It also requires module parameters write permission to reproduce the issue. That said, the consequence is quite bad. One reliable way to reproduce the issue is like below: # cd /sys/module/damon_lru_sort/parameters # echo 1000 > wmarks_high # echo 995 > wmarks_mid # echo 0 > wmarks_low # echo 10002 > active_mem_bp # echo Y > enabled # dmesg -w [...] [ 597.421247] Oops: divide error: 0000 [#1] SMP NOPTI [ 597.428848] RIP: 0010:damos_quota_score+0x6f/0x480 This issue was discovered [1] by Sashiko.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 40d98d31cd7060228e03303c5c34ae7101020416 e7e5e5e0dfe2ea171044c24c263efae4ee882b3f git Not specified
CNA Linux Linux affected 40d98d31cd7060228e03303c5c34ae7101020416 06befa61c427e74319781e6f35a364cfc32dbae8 git Not specified
CNA Linux Linux affected 7.0 Not specified
CNA Linux Linux unaffected 7.0 semver Not specified
CNA Linux Linux unaffected 7.1.9 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/06befa61c427e74319781e6f35a364cfc32dbae8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e7e5e5e0dfe2ea171044c24c263efae4ee882b3f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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