[PATCH] x86_64: Dump stack and prevent recursion on early fault

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S
index b6d8725c1f61..9bd2e7a4b81e 100644
--- a/arch/x86_64/kernel/head.S
+++ b/arch/x86_64/kernel/head.S
@@ -200,14 +200,22 @@ init_rsp:
         .quad  init_thread_union+THREAD_SIZE-8
 
 ENTRY(early_idt_handler)
+        cmpl $2,early_recursion_flag(%rip)
+        jz  1f
+        incl early_recursion_flag(%rip)
         xorl %eax,%eax
         movq 8(%rsp),%rsi       # get rip
         movq (%rsp),%rdx
         movq %cr2,%rcx
         leaq early_idt_msg(%rip),%rdi
         call early_printk
+        cmpl $2,early_recursion_flag(%rip)
+        jz  1f
+        call dump_stack
 1:      hlt
         jmp 1b
+early_recursion_flag:
+        .long 0
 
 early_idt_msg:
         .asciz "PANIC: early exception rip %lx error %lx cr2 %lx\n"