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: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index dcba6c5..c6520a4 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -273,6 +273,7 @@
preempt_disable();
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
+ WARN_ON(preempt_count() == 1);
arch_leave_lazy_mmu_mode();
arch_enter_lazy_mmu_mode();
}
@@ -285,6 +286,7 @@
preempt_disable();
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
+ WARN_ON(preempt_count() == 1);
arch_leave_lazy_cpu_mode();
arch_enter_lazy_cpu_mode();
}