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=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 0C3DDC433DF for ; Tue, 18 Aug 2020 16:24:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE7F22067C for ; Tue, 18 Aug 2020 16:24:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726910AbgHRQYK (ORCPT ); Tue, 18 Aug 2020 12:24:10 -0400 Received: from verein.lst.de ([213.95.11.211]:34171 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726398AbgHRQYI (ORCPT ); Tue, 18 Aug 2020 12:24:08 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id D0D1368AFE; Tue, 18 Aug 2020 18:24:04 +0200 (CEST) Date: Tue, 18 Aug 2020 18:24:04 +0200 From: Christoph Hellwig To: Coly Li Cc: linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, netdev@vger.kernel.org, open-iscsi@googlegroups.com, linux-scsi@vger.kernel.org, ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org, Chaitanya Kulkarni , Christoph Hellwig , Hannes Reinecke , Jan Kara , Jens Axboe , Mikhail Skorzhinskii , Philipp Reisner , Sagi Grimberg , Vlastimil Babka , stable@vger.kernel.org Subject: Re: [PATCH v7 1/6] net: introduce helper sendpage_ok() in include/linux/net.h Message-ID: <20200818162404.GA27196@lst.de> References: <20200818131227.37020-1-colyli@suse.de> <20200818131227.37020-2-colyli@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200818131227.37020-2-colyli@suse.de> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: ceph-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org I think we should go for something simple like this instead: --- >From 4867e158ee86ebd801b4c267e8f8a4a762a71343 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 18 Aug 2020 18:19:23 +0200 Subject: net: bypass ->sendpage for slab pages Sending Slab or tail pages into ->sendpage will cause really strange delayed oops. Prevent it right in the networking code instead of requiring drivers to work around the fact. Signed-off-by: Christoph Hellwig --- net/socket.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/socket.c b/net/socket.c index dbbe8ea7d395da..fbc82eb96d18ce 100644 --- a/net/socket.c +++ b/net/socket.c @@ -3638,7 +3638,12 @@ EXPORT_SYMBOL(kernel_getpeername); int kernel_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags) { - if (sock->ops->sendpage) + /* + * sendpage does manipulates the refcount of the passed in page, which + * does not work for Slab pages, or for tails of non-__GFP_COMP + * high order pages. + */ + if (sock->ops->sendpage && !PageSlab(page) && page_count(page) > 0) return sock->ops->sendpage(sock, page, offset, size, flags); return sock_no_sendpage(sock, page, offset, size, flags); -- 2.28.0