Index: branches/VBox-6.1/src/VBox/VMM/VMMR0/VMMR0JmpA-amd64.asm
===================================================================
--- branches/VBox-6.1/src/VBox/VMM/VMMR0/VMMR0JmpA-amd64.asm	(revision 136202)
+++ branches/VBox-6.1/src/VBox/VMM/VMMR0/VMMR0JmpA-amd64.asm	(revision 145695)
@@ -33,8 +33,15 @@
 
 ;; Workaround for linux 4.6 fast/slow syscall stack depth difference.
+;; Update: This got worse with linux 5.13 and CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT.
+;;         The x86 arch_exit_to_user_mode_prepare code limits the offset to 255,
+;;         while the generic limit is 1023.  See bugref:10064 for details.
 %ifdef VMM_R0_SWITCH_STACK
  %define STACK_FUZZ_SIZE 0
 %else
- %define STACK_FUZZ_SIZE 128
+ %ifdef RT_OS_LINUX
+  %define STACK_FUZZ_SIZE 384
+ %else
+  %define STACK_FUZZ_SIZE 128
+ %endif
 %endif
 
