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Commit 34b0900d authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86: warn if arch_flush_lazy_mmu_cpu is called in preemptible context 



Impact: Catch cases where lazy MMU state is active in a preemtible context

arch_flush_lazy_mmu_cpu() has been changed to disable preemption so
the checks in enter/leave will never trigger. Put the preemtible()
check into arch_flush_lazy_mmu_cpu() to catch such cases.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent d85cf93d

arch/x86/kernel/paravirt.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -273,6 +273,7 @@ void arch_flush_lazy_mmu_mode(void) 
	preempt_disable();

	preempt_disable();





	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {

	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {

		WARN_ON(preempt_count() == 1);

		arch_leave_lazy_mmu_mode();

		arch_leave_lazy_mmu_mode();

		arch_enter_lazy_mmu_mode();

		arch_enter_lazy_mmu_mode();

	}

	}
@@ -285,6 +286,7 @@ void arch_flush_lazy_cpu_mode(void) 
	preempt_disable();

	preempt_disable();





	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {

	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {

		WARN_ON(preempt_count() == 1);

		arch_leave_lazy_cpu_mode();

		arch_leave_lazy_cpu_mode();

		arch_enter_lazy_cpu_mode();

		arch_enter_lazy_cpu_mode();

	}

	}