From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC734C433DF for ; Thu, 20 Aug 2020 07:52:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD5FC2076E for ; Thu, 20 Aug 2020 07:52:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cLxHqEj+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726836AbgHTHwk (ORCPT ); Thu, 20 Aug 2020 03:52:40 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:39967 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726723AbgHTHwi (ORCPT ); Thu, 20 Aug 2020 03:52:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597909957; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UofsnEJINhsLZveMoOdeZsh1+kYmfm7tCHhdeFiL1Kg=; b=cLxHqEj+KniKboG+2ZjdEHgOo4z3n4crEjR2D/y9r9HQoM2uYuEGCHoLYeMVgg7OO8FmQC xjN7xv+1w5DogRmLANDcIU1yVqIPX1ryERSGBx9rkpcW8BGk+z04SxJNQ4LzP+TTNDmoLT GJzHzsIUDaQv+D75ttGkM4RP0Tdpw/8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-160-oGjafM6mPxyBZsJ-RQGhJQ-1; Thu, 20 Aug 2020 03:52:35 -0400 X-MC-Unique: oGjafM6mPxyBZsJ-RQGhJQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B9E9D186A56F; Thu, 20 Aug 2020 07:52:34 +0000 (UTC) Received: from carbon (unknown [10.40.208.64]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9F7285DA30; Thu, 20 Aug 2020 07:52:23 +0000 (UTC) Date: Thu, 20 Aug 2020 09:52:22 +0200 From: Jesper Dangaard Brouer To: Lorenzo Bianconi Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net, lorenzo.bianconi@redhat.com, echaudro@redhat.com, sameehj@amazon.com, kuba@kernel.org, brouer@redhat.com Subject: Re: [PATCH net-next 4/6] xdp: add multi-buff support to xdp_return_{buff/frame} Message-ID: <20200820095222.711ccfa7@carbon> In-Reply-To: <7ff49193140f3cb5341732612c72bcc2c5fb3372.1597842004.git.lorenzo@kernel.org> References: <7ff49193140f3cb5341732612c72bcc2c5fb3372.1597842004.git.lorenzo@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, 19 Aug 2020 15:13:49 +0200 Lorenzo Bianconi wrote: > diff --git a/net/core/xdp.c b/net/core/xdp.c > index 884f140fc3be..006b24b5d276 100644 > --- a/net/core/xdp.c > +++ b/net/core/xdp.c > @@ -370,19 +370,55 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct) > > void xdp_return_frame(struct xdp_frame *xdpf) > { > + struct skb_shared_info *sinfo; > + int i; > + > __xdp_return(xdpf->data, &xdpf->mem, false); There is a use-after-free race here. The xdpf->data contains the shared_info (xdp_get_shared_info_from_frame(xdpf)). Thus you cannot free/return the page and use this data area below. > + if (!xdpf->mb) > + return; > + > + sinfo = xdp_get_shared_info_from_frame(xdpf); > + for (i = 0; i < sinfo->nr_frags; i++) { > + struct page *page = skb_frag_page(&sinfo->frags[i]); > + > + __xdp_return(page_address(page), &xdpf->mem, false); > + } > } > EXPORT_SYMBOL_GPL(xdp_return_frame); > > void xdp_return_frame_rx_napi(struct xdp_frame *xdpf) > { > + struct skb_shared_info *sinfo; > + int i; > + > __xdp_return(xdpf->data, &xdpf->mem, true); Same issue. > + if (!xdpf->mb) > + return; > + > + sinfo = xdp_get_shared_info_from_frame(xdpf); > + for (i = 0; i < sinfo->nr_frags; i++) { > + struct page *page = skb_frag_page(&sinfo->frags[i]); > + > + __xdp_return(page_address(page), &xdpf->mem, true); > + } > } > EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi); > > void xdp_return_buff(struct xdp_buff *xdp) > { > + struct skb_shared_info *sinfo; > + int i; > + > __xdp_return(xdp->data, &xdp->rxq->mem, true); Same issue. > + if (!xdp->mb) > + return; > + > + sinfo = xdp_get_shared_info_from_buff(xdp); > + for (i = 0; i < sinfo->nr_frags; i++) { > + struct page *page = skb_frag_page(&sinfo->frags[i]); > + > + __xdp_return(page_address(page), &xdp->rxq->mem, true); > + } > } -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer