CVE-2024-50207

Name	CVE-2024-50207
Description	In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix reader locking when changing the sub buffer order The function ring_buffer_subbuf_order_set() updates each ring_buffer_per_cpu and installs new sub buffers that match the requested page order. This operation may be invoked concurrently with readers that rely on some of the modified data, such as the head bit (RB_PAGE_HEAD), or the ring_buffer_per_cpu.pages and reader_page pointers. However, no exclusive access is acquired by ring_buffer_subbuf_order_set(). Modifying the mentioned data while a reader also operates on them can then result in incorrect memory access and various crashes. Fix the problem by taking the reader_lock when updating a specific ring_buffer_per_cpu in ring_buffer_subbuf_order_set().
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	vulnerable
	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	(unfixed)	end-of-life
linux	source	bullseye	(not affected)
linux	source	bookworm	(not affected)
linux	source	(unstable)	6.11.6-1

Notes

[bookworm] - linux <not-affected> (Vulnerable code not present)
[bullseye] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/09661f75e75cb6c1d2d8326a70c311d46729235f (6.12-rc4)