diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 2ac37372ef52..8e12fcbb2c63 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -128,6 +128,15 @@ static void flush_context(unsigned int cpu)
 			asid = 0;
 		} else {
 			asid = atomic64_xchg(&per_cpu(active_asids, i), 0);
+			/*
+			 * If this CPU has already been through a
+			 * rollover, but hasn't run another task in
+			 * the meantime, we must preserve its reserved
+			 * ASID, as this is the only trace we have of
+			 * the process it is still running.
+			 */
+			if (asid == 0)
+				asid = per_cpu(reserved_asids, i);
 			__set_bit(ASID_TO_IDX(asid), asid_map);
 		}
 		per_cpu(reserved_asids, i) = asid;