CVE-2021-46937: mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()'

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-02-27 · updated 2026-06-17
Weakness: CWE-668

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.

Affected products

Linux kernel: from 5.15.0 before 5.15.13 — fixed in 5.15.13

How to fix

Upgrade to a fixed version: Linux kernel 5.15.13. Check the vendor advisory for mitigations.

References

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