Linux Kernel OcteonTX2-PF GFP_KERNEL Misuse in Atomic Context Vulnerability

A vulnerability exists in the Linux kernel's OcteonTX2-PF driver due to the improper use of GFP_KERNEL in atomic context, particularly in real-time (RT) kernels. This issue can lead to sleep-related warnings, as the blockable memory allocation disrupts the expected atomic operations. The vulnerability arises from a commit intended to fix similar issues in non-RT kernels, but it inadvertently reintroduced the problem in RT environments by allowing sleeping functions to be called from invalid contexts, potentially leading to deadlocks or other synchronization issues.

Impact

Exploitation of this vulnerability can cause sleeping functions to be called inappropriately from atomic contexts, leading to potential deadlocks or other synchronization problems in the kernel.

Reproduction

The vulnerability can be reproduced on a Marvell OcteonTX CN96XX board running a Yocto RT kernel. The issue manifests during the initialization of hardware resources for the OcteonTX2-PF driver, where the improper GFP_KERNEL usage in atomic context triggers sleep warnings. This can be observed by monitoring the kernel logs for sleeping function warnings, which indicate that the vulnerability has been successfully reproduced.