MFC r304313:

  Teach netisr_get_cpuid() to limit a given value to supported by netisr.
  Use netisr_get_cpuid() in netisr_select_cpuid() to limit cpuid value
  returned by protocol to be sure that it is not greather than nws_count.

  PR:		211836

2 files changed, 7 insertions, 8 deletions

diff --git a/sys/net/if_epair.c b/sys/net/if_epair.c
index 86e8379..6ac65c6 100644
--- a/sys/net/if_epair.c
+++ b/sys/net/if_epair.c
@@ -807,9 +807,9 @@ epair_clone_create(struct if_clone *ifc, char *name, size_t len, caddr_t params)
 	 * cache locality but we can at least allow parallelism.
 	 */
 	sca->cpuid =
-	    netisr_get_cpuid(sca->ifp->if_index % netisr_get_cpucount());
+	    netisr_get_cpuid(sca->ifp->if_index);
 	scb->cpuid =
-	    netisr_get_cpuid(scb->ifp->if_index % netisr_get_cpucount());
+	    netisr_get_cpuid(scb->ifp->if_index);
 
 	/* Initialise pseudo media types. */
 	ifmedia_init(&sca->media, 0, epair_media_change, epair_media_status);
diff --git a/sys/net/netisr.c b/sys/net/netisr.c
index 318e1a3..931d86c 100644
--- a/sys/net/netisr.c
+++ b/sys/net/netisr.c
@@ -272,10 +272,7 @@ u_int
 netisr_get_cpuid(u_int cpunumber)
 {
 
-	KASSERT(cpunumber < nws_count, ("%s: %u > %u", __func__, cpunumber,
-	    nws_count));
-
-	return (nws_array[cpunumber]);
+	return (nws_array[cpunumber % nws_count]);
 }
 
 /*
@@ -810,10 +807,12 @@ netisr_select_cpuid(struct netisr_proto *npp, u_int dispatch_policy,
 		 * dispatch.  In the queued case, fall back on the SOURCE
 		 * policy.
 		 */
-		if (*cpuidp != NETISR_CPUID_NONE)
+		if (*cpuidp != NETISR_CPUID_NONE) {
+			*cpuidp = netisr_get_cpuid(*cpuidp);
 			return (m);
+		}
 		if (dispatch_policy == NETISR_DISPATCH_HYBRID) {
-			*cpuidp = curcpu;
+			*cpuidp = netisr_get_cpuid(curcpu);
 			return (m);
 		}
 		policy = NETISR_POLICY_SOURCE;