CVE-2024-35968: 
Linux Kernel vulnerability analysis and mitigation

CVE-2024-35968 affects the Linux kernel's pds_core driver. The vulnerability was discovered in the pdsc_check_pci_health function, where a deadlock condition occurs when the driver attempts to perform a PCI reset on itself via pci_reset_function() while in the driver's health thread context. This issue affects Linux kernel versions from 6.6.16 up to 6.7, 6.7.4 up to 6.8.7, and 6.9 release candidates (rc1, rc2, rc3) (NVD).

The vulnerability stems from a race condition in the pdsc_check_pci_health function. When the driver detects fw_status == 0xff, it attempts to perform a PCI reset through pci_reset_function(). However, pdsc_reset_prepare calls pdsc_stop_health_thread(), which tries to stop/flush the health thread. This creates a deadlock since the stop/flush operation cannot complete as the driver called pci_reset_function() from within the health thread context. The vulnerability has been assigned 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).

The vulnerability can result in a system deadlock when the driver attempts to perform a PCI reset operation. This can lead to a denial of service condition, affecting system availability. The impact is particularly significant when unloading the driver in the fw_down/dead state (Kernel Patch).

The vulnerability requires local access with low privileges to exploit. No remote exploitation vectors have been identified. The attack complexity is considered low, as it doesn't require special conditions or preparation to execute (NVD).

The vulnerability has been patched by modifying the pdsc_check_pci_health_function() to queue a newly introduced pdsc_pci_reset_thread() on the pdsc's work queue. Additionally, the fix prevents devcmd reset if the firmware is not running. The patch has been incorporated into the Linux kernel codebase (Kernel Patch).