--- a/vboxguest/r0drv/linux/mp-r0drv-linux.c
+++ a/vboxguest/r0drv/linux/mp-r0drv-linux.c
@@ -283,12 +283,15 @@
     if (RTCpuSetCount(&OnlineSet) > 1)
     {
         /* Fire the function on all other CPUs without waiting for completion. */
-# if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
+# if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 3, 0)
+        smp_call_function(rtmpLinuxAllWrapper, &Args, 0 /* wait */);
+# elif LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
         int rc = smp_call_function(rtmpLinuxAllWrapper, &Args, 0 /* wait */);
+        Assert(!rc); NOREF(rc);
 # else
         int rc = smp_call_function(rtmpLinuxAllWrapper, &Args, 0 /* retry */, 0 /* wait */);
-# endif
         Assert(!rc); NOREF(rc);
+# endif
     }
 #endif

@@ -326,7 +329,6 @@
 {
 #ifdef CONFIG_SMP
     IPRT_LINUX_SAVE_EFL_AC();
-    int rc;
     RTMPARGS Args;

     RTTHREADPREEMPTSTATE PreemptState = RTTHREADPREEMPTSTATE_INITIALIZER;
@@ -337,14 +339,17 @@
     Args.cHits = 0;

     RTThreadPreemptDisable(&PreemptState);
-# if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
-    rc = smp_call_function(rtmpLinuxWrapper, &Args, 1 /* wait */);
+# if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 3, 0)
+    smp_call_function(rtmpLinuxWrapper, &Args, 1 /* wait */);
+# elif LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
+    int rc = smp_call_function(rtmpLinuxWrapper, &Args, 1 /* wait */);
+    Assert(rc == 0); NOREF(rc);
 # else /* older kernels */
-    rc = smp_call_function(rtmpLinuxWrapper, &Args, 0 /* retry */, 1 /* wait */);
+    int rc = smp_call_function(rtmpLinuxWrapper, &Args, 0 /* retry */, 1 /* wait */);
+    Assert(rc == 0); NOREF(rc);
 # endif /* older kernels */
     RTThreadPreemptRestore(&PreemptState);

-    Assert(rc == 0); NOREF(rc);
     IPRT_LINUX_RESTORE_EFL_AC();
 #else
     RT_NOREF(pfnWorker, pvUser1, pvUser2);