Re: PATCH: Fix poor pointer math in devinet_sysctl_register

[Andrew Morton <akpm@osdl.org>]

"Jordan Crouse" <jordan.crouse@amd.com> wrote:
>
> This patch fixes pointer math that under certain circumstances, results
>  in really bad pointers. This was encountered on a system compiled for i486, so
>  other compilers may differ, but I don't think it hurts anyone.
> 
>  Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
>  ---
> 
>   net/ipv4/devinet.c |    2 +-
>   1 files changed, 1 insertions(+), 1 deletions(-)
> 
>  diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
>  index 4ec4b2c..7585fce 100644
>  --- a/net/ipv4/devinet.c
>  +++ b/net/ipv4/devinet.c
>  @@ -1454,7 +1454,7 @@ static void devinet_sysctl_register(stru
>   		return;
>   	memcpy(t, &devinet_sysctl, sizeof(*t));
>   	for (i = 0; i < ARRAY_SIZE(t->devinet_vars) - 1; i++) {
>  -		t->devinet_vars[i].data += (char *)p - (char *)&ipv4_devconf;
>  +		t->devinet_vars[i].data += (int)((char *)p - (char *)&ipv4_devconf);

Confused.  These appear to be equivalent (on 32-bit CPUs, anyway).