Executive brief
The Linux kernel's DAMON (Data Access Monitoring) subsystem has a memory leak in its target process ID management. When certain monitoring configuration changes fail partway through, process IDs may not be properly released, wasting system memory. While the specific failure conditions are rare in typical deployments, they can occur when monitoring very large numbers of memory regions.
Technical details
This is a resource leak vulnerability in mm/damon/core.c affecting the damon_commit_target() function. The vulnerability occurs when a context commit operation (used to update monitoring parameters) fails after some target process IDs have been partially committed. The root cause is that the destination context may lack the cleanup_target() callback needed to release these PIDs if it was not originally using the virtual address monitoring operation set. An attacker with capability to trigger DAMON operations (typically requiring kernel access or special privileges) could intentionally cause commit failures and leak process ID references. The fix ensures that leaked PIDs are properly released during error handling in the commit operation. Patches are available in upstream kernel repositories.
Affected products
- Linux Linux kernel prior to fix
Timeline
- 2026-08-15: disclosed