diff --git a/arch/alpha/include/asm/mmu_context.h b/arch/alpha/include/asm/mmu_context.h
index d366f89fee58..f41d7c73fdd6 100644
--- a/arch/alpha/include/asm/mmu_context.h
+++ b/arch/alpha/include/asm/mmu_context.h
@@ -162,8 +162,8 @@ ev5_switch_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm,
 		next_mm->context[cpu] = mmc;
 	}
 #ifdef CONFIG_SMP
-	else
-		cpu_data[cpu].need_new_asn = 1;
+	/* A deferred shootdown can also invalidate a newly allocated ASN. */
+	cpu_data[cpu].need_new_asn = 1;
 #endif
 
 	/* Always update the PCB ASN.  Another thread may have allocated
@@ -192,6 +192,17 @@ do {								\
 #define check_mmu_context()  do { } while(0)
 #endif
 
+/*
+ * Also called from kthread_use_mm() with preemption enabled. Alpha has
+ * no kernel preemption, so the task is still on the CPU that ran
+ * switch_mm().
+ */
+#define finish_arch_post_lock_switch finish_arch_post_lock_switch
+static inline void finish_arch_post_lock_switch(void)
+{
+	check_mmu_context();
+}
+
 __EXTERN_INLINE void
 ev5_activate_mm(struct mm_struct *prev_mm, struct mm_struct *next_mm)
 {
diff --git a/arch/alpha/include/asm/switch_to.h b/arch/alpha/include/asm/switch_to.h
index 762b7f975310..35c4b2c9d992 100644
--- a/arch/alpha/include/asm/switch_to.h
+++ b/arch/alpha/include/asm/switch_to.h
@@ -9,7 +9,6 @@ extern struct task_struct *alpha_switch_to(unsigned long, struct task_struct *);
 #define switch_to(P,N,L)						 \
   do {									 \
     (L) = alpha_switch_to(virt_to_phys(&task_thread_info(N)->pcb), (P)); \
-    check_mmu_context();						 \
   } while (0)
 
 #endif /* __ALPHA_SWITCH_TO_H */