[Xen-devel] Re: libxc: fix bug of xc_tbuf_get_size()

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

When did this change, and who changed it? It would be good to collect an
appropriate Ack, e.g., from George Dunlap, if it was his xentrace changes.

I can't take un-acked patches from non-maintainers on stuff I don't have
good knowledge of myself, this late in the release cycle.

 -- Keir

On 09/02/2010 10:57, "Yu Zhiguo" <yuzg@xxxxxxxxxxxxxx> wrote:

> The size in pages of trace buffer should be t_info->tbuf_size
> rather than t_info pages.
> 
> Signed-off-by: Yu Zhiguo <yuzg@xxxxxxxxxxxxxx>
> 
> diff --git a/tools/libxc/xc_tbuf.c b/tools/libxc/xc_tbuf.c
> --- a/tools/libxc/xc_tbuf.c
> +++ b/tools/libxc/xc_tbuf.c
> @@ -15,6 +15,7 @@
>   */
>  
>  #include "xc_private.h"
> +#include <xen/trace.h>
>  
>  static int tbuf_enable(int xc_handle, int enable)
>  {
> @@ -44,6 +45,7 @@
>  
>  int xc_tbuf_get_size(int xc_handle, unsigned long *size)
>  {
> +    struct t_info *t_info;
>      int rc;
>      DECLARE_SYSCTL;
>  
> @@ -52,9 +54,19 @@
>      sysctl.u.tbuf_op.cmd  = XEN_SYSCTL_TBUFOP_get_info;
>  
>      rc = xc_sysctl(xc_handle, &sysctl);
> -    if (rc == 0)
> -        *size = sysctl.u.tbuf_op.size;
> -    return rc;
> +    if ( rc != 0 )
> +        return rc;
> +
> +    t_info = xc_map_foreign_range(xc_handle, DOMID_XEN,
> +                    sysctl.u.tbuf_op.size, PROT_READ | PROT_WRITE,
> +                    sysctl.u.tbuf_op.buffer_mfn);
> +
> +    if ( t_info == NULL || t_info->tbuf_size == 0 )
> +        return -1;
> +
> +    *size = t_info->tbuf_size;
> +
> +    return 0;
>  }
>  
>  int xc_tbuf_enable(int xc_handle, unsigned long pages, unsigned long *mfn,
> 



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