Linux Kernel DAMON Repeat Call Control Memory Leak Vulnerability

A memory leak vulnerability has been identified in the Linux kernel's DAMON (Data Access Monitoring) subsystem, specifically within the sysfs interface. This issue arises when the 'damon_call()' function for the repeat_call_control of DAMON_SYSFS fails, particularly if the kdamond (the DAMON kernel daemon) is stopped before the call can be made. Such a scenario can occur if the DAMON context is set up to monitor a process that is terminated immediately, leading to a situation where the dynamically allocated repeat_call_control is not properly deallocated, causing a memory leak. The vulnerability has been addressed by modifying the code to ensure that the repeat_call_control is deallocated if the damon_call() fails.

Impact

Exploitation of this vulnerability leads to a memory leak, where allocated memory is not properly released, potentially causing increased memory usage and degradation of system performance over time.

Reproduction

To reproduce this vulnerability, create a DAMON context for monitoring a process's virtual address. Immediately terminate the process before the 'damon_call()' invocation. This will cause the 'damon_call()' to fail, leaving the dynamically allocated 'repeat_call_control' undeallocated and leaked.

Remediation

Users can upgrade to the latest version of the Linux kernel where this vulnerability has been fixed. Instructions for upgrading the Linux kernel can be found in the official Linux documentation.