From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: X-Spam-Status: No, score=-2.9 required=3.0 tests=ALL_TRUSTED,BAYES_00, URIBL_BLOCKED shortcircuit=no autolearn=unavailable version=3.3.2 X-Original-To: yahns-public@yhbt.net Received: from localhost (dcvr.yhbt.net [127.0.0.1]) by dcvr.yhbt.net (Postfix) with ESMTP id 0458E1F49F for ; Sat, 7 Mar 2015 21:36:44 +0000 (UTC) Date: Sat, 7 Mar 2015 21:36:44 +0000 From: Eric Wong To: yahns-public@yhbt.net Subject: Re: [PATCH 2/2] wbuf: avoid corrupted large responses with zero-copy sendfile Message-ID: <20150307213644.GA26034@dcvr.yhbt.net> References: <1405540640-10669-1-git-send-email-e@80x24.org> <1405540640-10669-3-git-send-email-e@80x24.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1405540640-10669-3-git-send-email-e@80x24.org> List-Id: Eric Wong wrote: > This bug is noticeable on a amd64 FreeBSD 9.2 VM, and possible under > Linux, too. This happens as a zero-copy sendfile implementation means > pages queued for transmission by the sendfile system call should not be > modified at any point after the sendfile syscall is made. Btw, this gotcha is now noted in the Linux sendfile(2) manpage: http://git.kernel.org/cgit/docs/man-pages/man-pages.git/commit/man2/sendfile.2?id=7b6a3299776b5c1c4f169a591434a855d50c68b4