Re: [PATCH] kdump: Append newline to the last lien of vmcoreinfo note

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 17 Jul 2012 13:36:55 -0400
Vivek Goyal <vgoyal@redhat.com> wrote:

> Last line of vmcoreinfo note does not end with \n. Parsing all the lines
> in note becomes easier if all lines end with \n instead of trying to special
> case the last line.
> 
> I know atleast one tool, vmcore-dmesg in kexec-tools tree which made the
> assumption that all lines end with \n. I think it is a good idea to
> fix it.
> 
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> ---
>  kernel/kexec.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Index: linux-2.6/kernel/kexec.c
> ===================================================================
> --- linux-2.6.orig/kernel/kexec.c	2012-07-17 19:26:38.844033784 -0400
> +++ linux-2.6/kernel/kexec.c	2012-07-17 23:51:33.311701781 -0400
> @@ -1424,7 +1424,7 @@ static void update_vmcoreinfo_note(void)
>  
>  void crash_save_vmcoreinfo(void)
>  {
> -	vmcoreinfo_append_str("CRASHTIME=%ld", get_seconds());
> +	vmcoreinfo_append_str("CRASHTIME=%ld\n", get_seconds());
>  	update_vmcoreinfo_note();
>  }

huh, that was a screwup.  And now we have to make what must be
viewed as a non-back-compatible ABI change.

Ho hum, presumably there isn't a lot of code out there which is
dependent upon a non-newline-terminated CRASHTIME record.

Why did this work at all, anyway?  Is CRASHTIME always the last-emitted
record?