[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>

diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S
index b6d8725..9bd2e7a 100644 (file)
--- 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"