RE: [PATCH rdma-next] RDMA/core: Fix broadcast address falsely detected as local

[Parav Pandit]

> From: Edward Srouji <edwards@xxxxxxxxxx>
> Sent: 09 June 2026 04:47 PM
> 
> From: Maher Sanalla <msanalla@xxxxxxxxxx>
> 
> When rdma_resolve_addr() is invoked with a broadcast destination on an
> IPoIB interface, is_dst_local() inspects the resolved route and
> incorrectly concludes that the address is local. As a result, the
> resolution fails with -ENODEV.
> The issue stems from using '&' to compare rt_type with RTN_LOCAL. The
> RTN_* values form a sequential enum, not a bitmask (RTN_LOCAL=2,
> RTN_BROADCAST=3). Thus, "rt_type & RTN_LOCAL" yields a non-zero result
> for a broadcast route as well.
> 
> Replace '&' with '==' when comparing rt_type against RTN_LOCAL.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: c31e4038c97f ("RDMA/core: Use route entry flag to decide on loopback traffic")
> Signed-off-by: Maher Sanalla <msanalla@xxxxxxxxxx>
> Reviewed-by: Vlad Dumitrescu <vdumitrescu@xxxxxxxxxx>
> Signed-off-by: Edward Srouji <edwards@xxxxxxxxxx>
> ---
>  drivers/infiniband/core/addr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c
> index 7e62b5b1ffaa364ce0720a09084beca5f4db95a5..e9fb7ad4c377cfe4605b12ed4b4be2e5dba7eb13 100644
> --- a/drivers/infiniband/core/addr.c
> +++ b/drivers/infiniband/core/addr.c
> @@ -438,7 +438,7 @@ static int addr6_resolve(struct sockaddr *src_sock,
>  static bool is_dst_local(const struct dst_entry *dst)
>  {
>  	if (dst->ops->family == AF_INET)
> -		return !!(dst_rtable(dst)->rt_type & RTN_LOCAL);
> +		return dst_rtable(dst)->rt_type == RTN_LOCAL;
>  	else if (dst->ops->family == AF_INET6)
>  		return !!(dst_rt6_info(dst)->rt6i_flags & RTF_LOCAL);
>  	else
> 
> ---
> base-commit: ea4f6f6c53577fb3f05dbd78b15e586772d49831
> change-id: 20260609-fix-rdma-resolve-addr-1ce615248b6a
> 
> Best regards,
> --
> Edward Srouji <edwards@xxxxxxxxxx>

Reviewed-by: Parav Pandit <parav@xxxxxxxxxx>