CVE-2021-46937

Name	CVE-2021-46937
Description	In the Linux kernel, the following vulnerability has been resolved: mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()' DAMON debugfs interface increases the reference counts of 'struct pid's for targets from the 'target_ids' file write callback ('dbgfs_target_ids_write()'), but decreases the counts only in DAMON monitoring termination callback ('dbgfs_before_terminate()'). Therefore, when 'target_ids' file is repeatedly written without DAMON monitoring start/termination, the reference count is not decreased and therefore memory for the 'struct pid' cannot be freed. This commit fixes this issue by decreasing the reference counts when 'target_ids' is written.
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)	buster	4.19.249-2	fixed
	buster (security)	4.19.304-1	fixed
	bullseye	5.10.209-2	vulnerable
	bullseye (security)	5.10.205-2	vulnerable
	bookworm	6.1.76-1	fixed
	bookworm (security)	6.1.85-1	fixed
	trixie	6.6.15-2	fixed
	sid	6.7.12-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
linux	source	buster	(not affected)
linux	source	(unstable)	5.15.15-1

[buster] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/ebb3f994dd92f8fb4d70c7541091216c1e10cb71 (5.16-rc8)