CVE-2024-35985

Name	CVE-2024-35985
Description	In the Linux kernel, the following vulnerability has been resolved: sched/eevdf: Prevent vlag from going out of bounds in reweight_eevdf() It was possible to have pick_eevdf() return NULL, which then causes a NULL-deref. This turned out to be due to entity_eligible() returning falsely negative because of a s64 multiplcation overflow. Specifically, reweight_eevdf() computes the vlag without considering the limit placed upon vlag as update_entity_lag() does, and then the scaling multiplication (remember that weight is 20bit fixed point) can overflow. This then leads to the new vruntime being weird which then causes the above entity_eligible() to go side-ways and claim nothing is eligible. Thus limit the range of vlag accordingly. All this was quite rare, but fatal when it does happen.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	jessie, jessie (lts)	3.16.84-1	vulnerable
	stretch (security)	4.9.320-2	vulnerable
	stretch (lts), stretch	4.9.320-3	vulnerable
	buster (security), buster, buster (lts)	4.19.316-1	fixed
	bullseye	5.10.223-1	fixed
	bullseye (security)	5.10.226-1	fixed
	bookworm	6.1.115-1	fixed
	bookworm (security)	6.1.119-1	fixed
	trixie	6.12.5-1	fixed
	sid	6.12.6-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency
linux	source	jessie	(unfixed)	end-of-life
linux	source	stretch	(unfixed)	end-of-life
linux	source	buster	(not affected)
linux	source	bullseye	(not affected)
linux	source	bookworm	(not affected)
linux	source	(unstable)	6.8.9-1

Notes

[bookworm] - linux <not-affected> (Vulnerable code not present)
[bullseye] - linux <not-affected> (Vulnerable code not present)
[buster] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/1560d1f6eb6b398bddd80c16676776c0325fe5fe (6.9-rc6)