Linux Kernel IRQ Restoration Vulnerability in Sched_ext Component

A vulnerability in the Linux kernel's sched_ext component has been addressed. The issue arose from an improper interrupt request (IRQ) restoration in the 'scx_ops_bypass()' function. When implementing additional outer IRQ save/restore locking, the change inadvertently left an inner 'rq_unlock_irqrestore()' unconverted. This oversight could have prematurely re-enabled IRQs, triggering a warning about the raw_local_irq_restore() being called with IRQs already enabled. The warning indicated a potential race condition that could be exploited.

Impact

The vulnerability could lead to a race condition by allowing interrupts to be re-enabled prematurely, potentially causing erratic behavior in the scheduling operations.