Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755411AbbLaKxy (ORCPT ); Thu, 31 Dec 2015 05:53:54 -0500 Received: from mail-wm0-f47.google.com ([74.125.82.47]:34474 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751215AbbLaKxv (ORCPT ); Thu, 31 Dec 2015 05:53:51 -0500 From: Nicolai Stange To: David Miller Cc: nicstange@gmail.com, edumazet@google.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] net, socket, socket_wq: fix missing initialization of flags References: <87ege73bma.fsf@gmail.com> <1451323186.8255.5.camel@edumazet-glaptop2.roam.corp.google.com> <87ziwtphdo.fsf_-_@gmail.com> <20151230.163915.990334768673899184.davem@davemloft.net> Date: Thu, 31 Dec 2015 11:53:48 +0100 In-Reply-To: <20151230.163915.990334768673899184.davem@davemloft.net> (David Miller's message of "Wed, 30 Dec 2015 16:39:15 -0500 (EST)") Message-ID: <8760ze99dv.fsf@gmail.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2066 Lines: 45 David Miller writes: > From: Nicolai Stange > Date: Tue, 29 Dec 2015 13:29:55 +0100 > >> Fixes: ceb5d58b2170 ("net: fix sock_wake_async() rcu protection") >> >> Commit ceb5d58b2170 ("net: fix sock_wake_async() rcu protection") from >> the current 4.4 release cycle introduced a new flags member in >> struct socket_wq and moved SOCKWQ_ASYNC_NOSPACE and SOCKWQ_ASYNC_WAITDATA >> from struct socket's flags member into that new place. >> >> Unfortunately, the new flags field is never initialized properly, at least >> not for the struct socket_wq instance created in sock_alloc_inode(). >> >> One particular issue I encountered because of this is that my GNU Emacs >> failed to draw anything on my desktop -- i.e. what I got is a transparent >> window, including the title bar. Bisection lead to the commit mentioned >> above and further investigation by means of strace told me that Emacs >> is indeed speaking to my Xorg through an O_ASYNC AF_UNIX socket. This is >> reproducible 100% of times and the fact that properly initializing the >> struct socket_wq ->flags fixes the issue leads me to the conclusion that >> somehow SOCKWQ_ASYNC_WAITDATA got set in the uninitialized ->flags, >> preventing my Emacs from receiving any SIGIO's due to data becoming >> available and it got stuck. >> >> Make sock_alloc_inode() set the newly created struct socket_wq's ->flags >> member to zero. >> >> Signed-off-by: Nicolai Stange > > Applied, but please in the future please put the Fixes: tag right > above the first signoff/ack, like this: > > Fixes: ceb5d58b2170 ("net: fix sock_wake_async() rcu protection") > Signed-off-by: Nicolai Stange Thank you very much! Regarding the correct position of the "Fixes:" tag: lesson learned. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/