Re: Xen-unstable: "root=" no longer prepended on kernel cmdline since commit "tools: xl: handle unspecified extra= when dealing with root="

[Wei Liu <wei.liu2@citrix.com>]

On Thu, Mar 12, 2015 at 05:59:06PM +0000, Ian Campbell wrote:
> On Thu, 2015-03-12 at 18:48 +0100, Sander Eikelenboom wrote:
> > Hi Ian,
> > 
> > My PV-guest configs were still using the old "root=" option,
> > but these guests don't boot anymore since:
> > commit 49ab17a3a615e1ab4ccc46d6942f925cf841df4b,
> > "tools: xl: handle unspecified extra= when dealing with root="
> > 
> > These pv guests don't boot anymore since the "root=" part isn't
> > prepended anymore on the kernel commandline, leading to
> > a guest kernel that is incapable of finding the root partition.
> 
> Bugger, you are of course absolutely correct.
> 
> How about this, compile tested only...
> 
> 8<-------------
> 
> >From fc8eed8083d87608df7b836d89ba058066206b6c Mon Sep 17 00:00:00 2001
> From: Ian Campbell <ian.campbell@citrix.com>
> Date: Thu, 12 Mar 2015 17:56:47 +0000
> Subject: [PATCH] tools: xl: prepend root= to root field on command line with
>  no extra
> 
> This was broken in 49ab17a3a615 "tools: xl: handle unspecified extra=
> when dealing with root=".
> 
> Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

Acked-by: Wei Liu <wei.liu2@citrix.com>

> ---
>  tools/libxl/xl_cmdimpl.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> index 2c32a96..af5bd87 100644
> --- a/tools/libxl/xl_cmdimpl.c
> +++ b/tools/libxl/xl_cmdimpl.c
> @@ -821,7 +821,8 @@ static char *parse_cmdline(XLU_Config *config)
>              if (asprintf(&cmdline, "root=%s %s", root, extra) == -1)
>                  cmdline = NULL;
>          } else if (root) {
> -            cmdline = strdup(root);
> +            if (asprintf(&cmdline, "root=%s", root) == -1)
> +                cmdline = NULL;
>          } else if (extra) {
>              cmdline = strdup(extra);
>          }
> -- 
> 1.7.10.4
> 
>