Re: [Xen-devel] [PATCH] linux_gntshr_munmap: munmap takes a length, not a page count

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2014-09-01 at 13:16 +0100, David Scott wrote:
> This fixes a bug where if a client shares more than 1 page, the
> munmap call fails to clean up everything. A process which does
> a lot of sharing and unsharing can run out of resources.

The doc comment on xc_gntshr_munmap does say count is in pages, so your
change is correct but all of the in tree callers seem to pass a number
of bytes not a number of pages. i.e. everything in tools/libvchan passes
n*PAGE_SIZE.

So I don't think this change is complete without also updating those.

Ian.

> 
> Signed-off-by: David Scott <dave.scott@xxxxxxxxxx>
> ---
>  tools/libxc/xc_linux_osdep.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/libxc/xc_linux_osdep.c b/tools/libxc/xc_linux_osdep.c
> index 86bff3e..a19e4b6 100644
> --- a/tools/libxc/xc_linux_osdep.c
> +++ b/tools/libxc/xc_linux_osdep.c
> @@ -847,7 +847,7 @@ static void *linux_gntshr_share_pages(xc_gntshr *xch, 
> xc_osdep_handle h,
>  static int linux_gntshr_munmap(xc_gntshr *xcg, xc_osdep_handle h,
>                                 void *start_address, uint32_t count)
>  {
> -    return munmap(start_address, count);
> +    return munmap(start_address, count * XC_PAGE_SIZE);
>  }
>  
>  static struct xc_osdep_ops linux_gntshr_ops = {



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel