Bug 2391070 (CVE-2025-38519)

Summary:	CVE-2025-38519 kernel: mm/damon: fix divide by zero in damon_get_intervals_score()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	unspecified	Keywords:	Security
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Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2025-08-26 15:09:58 UTC

In the Linux kernel, the following vulnerability has been resolved:

mm/damon: fix divide by zero in damon_get_intervals_score()

The current implementation allows having zero size regions with no special
reasons, but damon_get_intervals_score() gets crashed by divide by zero
when the region size is zero.

  [   29.403950] Oops: divide error: 0000 [#1] SMP NOPTI

This patch fixes the bug, but does not disallow zero size regions to keep
the backward compatibility since disallowing zero size regions might be a
breaking change for some users.

In addition, the same crash can happen when intervals_goal.access_bp is
zero so this should be fixed in stable trees as well.

Comment 1 Jon Moroney 2025-08-26 15:42:52 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025081654-CVE-2025-38519-6cc4@gregkh/T