1 files changed, 11 insertions, 1 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 2255782e8d4b..0fa6790c1dd3 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -561,7 +561,13 @@ static void __init reserve_standard_io_resources(void)
 
 }
 
-#ifdef CONFIG_PROC_VMCORE
+/*
+ * Note: elfcorehdr_addr is not just limited to vmcore. It is also used by
+ * is_kdump_kernel() to determine if we are booting after a panic. Hence
+ * ifdef it under CONFIG_CRASH_DUMP and not CONFIG_PROC_VMCORE.
+ */
+
+#ifdef CONFIG_CRASH_DUMP
 /* elfcorehdr= specifies the location of elf core header
  * stored by the crashed kernel. This option will be passed
  * by kexec loader to the capture kernel.
@@ -1067,6 +1073,7 @@ void __init setup_arch(char **cmdline_p)
 #endif
 
         prefill_possible_map();
+
 #ifdef CONFIG_X86_64
         init_cpu_to_node();
 #endif
@@ -1074,6 +1081,9 @@ void __init setup_arch(char **cmdline_p)
         init_apic_mappings();
         ioapic_init_mappings();
 
+        /* need to wait for io_apic is mapped */
+        nr_irqs = probe_nr_irqs();
+
         kvm_guest_init();
 
         e820_reserve_resources();