Linux Kernel Memory Leak Vulnerability in IO Workers Management

A memory leak vulnerability has been identified in the Linux kernel's IO workers management system. When the allocation of a CPU mask for a node fails, the memory allocated for the 'io_wqe' structure is not released, leading to a leak. This issue occurs because the structure has not yet been added to the 'wqes' array. The vulnerability was discovered during fuzz testing of version 6.1-rc1 using Syzkaller, which revealed an unreferenced object leak of 1024 bytes.

Impact

Exploitation of this vulnerability leads to a memory leak, where allocated memory is not properly freed, causing unreferenced objects to remain in memory and potentially leading to increased memory usage over time.

Reproduction

The vulnerability can be reproduced by allocating IO workers with a faulty CPU mask allocation, which triggers the memory leak. This scenario was created during fuzz testing with Syzkaller, where the failed allocation did not allow for the proper cleanup of the 'io_wqe' structure, leaving the allocated memory unreferenced and leaked.

Remediation

Users can upgrade to the latest stable version of the Linux kernel to address this vulnerability.