[PATCH] x86_64: Add kernel thread stack frame termination for properly stopping stack...

One open question: Should these added pushes perhaps be made
conditional upon CONFIG_STACK_UNWIND or CONFIG_UNWIND_INFO?
[AK: Not needed -- these are all very slow paths]

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index 6f81042..aa8d893 100644 (file)
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -973,6 +973,8 @@ ENTRY(kernel_thread)
 ENDPROC(kernel_thread)
        
 child_rip:
+       pushq $0                # fake return address
+       CFI_STARTPROC
        /*
         * Here we are in the child and the registers are set as they were
         * at kernel_thread() invocation in the parent.
@@ -983,6 +985,7 @@ child_rip:
        # exit
        xorl %edi, %edi
        call do_exit
+       CFI_ENDPROC
 ENDPROC(child_rip)
 
 /*

diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S
index 6df05e6..c9739ca 100644 (file)
--- a/arch/x86_64/kernel/head.S
+++ b/arch/x86_64/kernel/head.S
@@ -191,6 +191,7 @@ startup_64:
         * jump
         */
        movq    initial_code(%rip),%rax
+       pushq   $0              # fake return address
        jmp     *%rax
 
        /* SMP bootup changes these two */