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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA4C5C4708E for ; Tue, 7 Nov 2023 00:16:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233507AbjKGAQ0 (ORCPT ); Mon, 6 Nov 2023 19:16:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230248AbjKGAQY (ORCPT ); Mon, 6 Nov 2023 19:16:24 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A941C0; Mon, 6 Nov 2023 16:16:22 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0EF7C433C8; Tue, 7 Nov 2023 00:16:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1699316181; bh=rdCTl+4hQmLubYiMS/p2QV8xEsJXv+ZSM2pgQqPjLVQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=LHFJpRRpE9spIepJHWhKG3x06BG5ePCOBuH4QJZkUidEwERp/tNEcGEPDfwoYcMsD LwQ+LDowdMk/nRme8Pe/2PP8U5mpI2/vbQhTfrjDmoqRK0P0GMn3klxMiSbaEGAvQx TxXq8Y5RvYtNAFTBQmRE6GfauJ63a/UJka/kDzDprGDEt16iWZR1vfQi3/2DP/Asai fs3QZ5heBo/8vttlafXTbhlXmNU5RDgI6S3oS67JNxncI/lQdczhxSDJGJZhgR1QIC kDsR5rXhwiQHG8PesuHnV3MhFJjuLD1YVEoyKFwdec07E1shE+t0tHzE2NG0moUC11 E/fd2myN6ldFA== Message-ID: Date: Mon, 6 Nov 2023 17:16:20 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v3 09/12] net: add support for skbs with unreadable frags Content-Language: en-US To: Mina Almasry , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jesper Dangaard Brouer , Ilias Apalodimas , Arnd Bergmann , Willem de Bruijn , Shuah Khan , Sumit Semwal , =?UTF-8?Q?Christian_K=C3=B6nig?= , Shakeel Butt , Jeroen de Borst , Praveen Kaligineedi , Willem de Bruijn , Kaiyuan Zhang References: <20231106024413.2801438-1-almasrymina@google.com> <20231106024413.2801438-10-almasrymina@google.com> From: David Ahern In-Reply-To: <20231106024413.2801438-10-almasrymina@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/5/23 7:44 PM, Mina Almasry wrote: > diff --git a/net/core/datagram.c b/net/core/datagram.c > index 176eb5834746..cdd4fb129968 100644 > --- a/net/core/datagram.c > +++ b/net/core/datagram.c > @@ -425,6 +425,9 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset, > return 0; > } > > + if (skb_frags_not_readable(skb)) > + goto short_copy; > + > /* Copy paged appendix. Hmm... why does this look so complicated? */ > for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { > int end; > @@ -616,6 +619,9 @@ int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk, > { > int frag; > > + if (skb_frags_not_readable(skb)) > + return -EFAULT; This check .... > + > if (msg && msg->msg_ubuf && msg->sg_from_iter) > return msg->sg_from_iter(sk, skb, from, length); ... should go here. That allows custome sg_from_iter to have access to the skb. What matters is not expecting struct page (e.g., refcounting); if the custom iter does not do that then all is well. io_uring's iter does not look at the pages, so all good. > > diff --git a/net/core/gro.c b/net/core/gro.c > index 42d7f6755f32..56046d65386a 100644 > --- a/net/core/gro.c > +++ b/net/core/gro.c > @@ -390,6 +390,9 @@ static void gro_pull_from_frag0(struct sk_buff *skb, int grow) > { > struct skb_shared_info *pinfo = skb_shinfo(skb); > > + if (WARN_ON_ONCE(skb_frags_not_readable(skb))) > + return; > + > BUG_ON(skb->end - skb->tail < grow); > > memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow); > @@ -411,7 +414,7 @@ static void gro_try_pull_from_frag0(struct sk_buff *skb) > { > int grow = skb_gro_offset(skb) - skb_headlen(skb); > > - if (grow > 0) > + if (grow > 0 && !skb_frags_not_readable(skb)) > gro_pull_from_frag0(skb, grow); > } > > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index 13eca4fd25e1..f01673ed2eff 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -1230,6 +1230,14 @@ void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt) > struct page *p; > u8 *vaddr; > > + if (skb_frag_is_page_pool_iov(frag)) { Why skb_frag_is_page_pool_iov here vs skb_frags_not_readable?