Linux Kernel RISC-V Sleeping Function Vulnerability in Exception Handler

A vulnerability exists in the Linux kernel for RISC-V architecture, where the 'die()' function can be called within an exception handler context that does not allow sleeping. The 'die()' function, however, takes a spinlock that can sleep when PREEMPT_RT is enabled, leading to a warning about sleeping functions being called from an invalid context. This issue was resolved by switching to a raw spinlock, which does not sleep even with PREEMPT_RT enabled.

Impact

The vulnerability could lead to a deadlock situation, where the system becomes unresponsive due to improper handling of sleep functions in a critical context.