Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

torvalds · torvalds · commit 42fd2b5006c3 · 2016-10-29T13:42:44.000-07:00
Pull x86 bugfix from Thomas Gleixner:
 "A single bugfix for the recent changes related to registering the boot
  cpu when this has not happened before prefill_possible_map().

  The main problem with this change got fixed already, but we missed the
  case where the local APIC is not yet mapped, when prefill_possible_map()
  is invoked, so the registration of the boot cpu which has the APIC bit
  set in CPUID will explode.

  I should have seen that issue earlier, but all I can do now is feeling
  embarassed"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/smpboot: Init apic mapping before usage
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
@@ -1221,11 +1221,16 @@ void __init setup_arch(char **cmdline_p)
 	 */
 	get_smp_config();
 
+	/*
+	 * Systems w/o ACPI and mptables might not have it mapped the local
+	 * APIC yet, but prefill_possible_map() might need to access it.
+	 */
+	init_apic_mappings();
+
 	prefill_possible_map();
 
 	init_cpu_to_node();
 
-	init_apic_mappings();
 	io_apic_init_mappings();
 
 	kvm_guest_init();
