CVE-2024-50122: 
Linux Kernel vulnerability analysis and mitigation

A race condition vulnerability was discovered in the Linux kernel (CVE-2024-50122) affecting PCI device handling. The issue occurs between the pwrctl platform device rescanning the bus and host controller probe functions, where a lack of proper locking can lead to an undefined state with incompletely added devices. This vulnerability affects Linux kernel versions from 6.11 up to (excluding) 6.11.6, and version 6.12 release candidates (rc1-rc4) (NVD).

The vulnerability stems from a missing rescan lock during device addition in the host probe process. When the PCI power control code attempts to rescan the bus while host controller probe functions are running, the lack of proper synchronization can result in a race condition. This can lead to a NULL pointer dereference when attempting to remove devices through sysfs. The issue has a CVSS v3.1 Base Score of 5.5 (Medium) with vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (NVD).

When exploited, this vulnerability can cause a system crash through a NULL pointer dereference, resulting in a denial of service condition. The issue manifests when attempting to remove a device through sysfs after the race condition has created an inconsistent device state (Kernel Patch).

The issue has been fixed in Linux kernel version 6.11.6 by adding proper locking mechanisms. The fix involves holding the rescan lock while adding devices during host probe by implementing pcilockrescanremove() and pciunlockrescanremove() calls around the pcibusadd_devices() function (Kernel Patch).