CVE-2023-52740

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> powerpc/64s/interrupt: Fix interrupt exit race with security mitigation switch<br /> <br /> The RFI and STF security mitigation options can flip the<br /> interrupt_exit_not_reentrant static branch condition concurrently with<br /> the interrupt exit code which tests that branch.<br /> <br /> Interrupt exit tests this condition to set MSR[EE|RI] for exit, then<br /> again in the case a soft-masked interrupt is found pending, to recover<br /> the MSR so the interrupt can be replayed before attempting to exit<br /> again. If the condition changes between these two tests, the MSR and irq<br /> soft-mask state will become corrupted, leading to warnings and possible<br /> crashes. For example, if the branch is initially true then false,<br /> MSR[EE] will be 0 but PACA_IRQ_HARD_DIS clear and EE may not get<br /> enabled, leading to warnings in irq_64.c.