From: jia zhang Date: Sun, 23 Nov 2008 14:47:10 +0000 (+0800) Subject: x86, debug: remove the confusing entry in call trace X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=5f5db591326779a80cfe490c5d6b6ce9fac08b31;p=deliverable%2Flinux.git x86, debug: remove the confusing entry in call trace Impact: improve backtrace quality avoid the confusion in call trace because of the lack of padding at the tail of function. When do_exit gets called, the return address behind call instruction is pushed into stack. If something get wrong in do_exit, for x86_64, the entry "kernel_execve +0x00/0xXX" rather than "child_rip +0xYY/0xZZ" is in the call trace. That looks confusing, so add a u2d to make the return address still part of the original call site. (This also catches any instances of us returning from that function somehow.) Signed-off-by: jia zhang Acked-by: Alexander van Heukelum Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 28b597ef9ca1..f6402c4ba10d 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -1051,6 +1051,7 @@ ENTRY(kernel_thread_helper) push %eax CFI_ADJUST_CFA_OFFSET 4 call do_exit + ud2 # padding for call trace CFI_ENDPROC ENDPROC(kernel_thread_helper) diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index ddeeb1052583..4a16bf31c783 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1172,6 +1172,7 @@ child_rip: # exit mov %eax, %edi call do_exit + ud2 # padding for call trace CFI_ENDPROC ENDPROC(child_rip)