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,AWL,BAYES_00, T_RP_MATCHES_RCVD shortcircuit=no autolearn=unavailable version=3.3.2 X-Original-To: normalperson@yhbt.net Received: from localhost (dcvr.yhbt.net [127.0.0.1]) by dcvr.yhbt.net (Postfix) with ESMTP id 2ED6D1F749; Thu, 17 Jan 2013 21:35:59 +0000 (UTC) Date: Thu, 17 Jan 2013 21:35:59 +0000 From: Eric Wong To: sleepy.penguin@librelist.org Subject: Re: [sleepy.penguin] [PATCH] epoll: avoid EPOLL_CTL_MOD race condition Message-ID: <20130117213559.GA12465@dcvr.yhbt.net> References: <20130103041904.GA29931@dcvr.yhbt.net> <20130103041904.GA29931@dcvr.yhbt.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130103041904.GA29931@dcvr.yhbt.net> User-Agent: Mutt/1.5.21 (2010-09-15) List-Id: Eric Wong wrote: > Until everybody updates to a version of the Linux kernel with > this fix, we need to enable a workaround for older kernels using > EPOLL_CTL_DEL + EPOLL_CTL_ADD to emulate EPOLL_CTL_MOD behavior. > > This race condition is fixed in Linux upstream > commit 128dd1759d96ad36c379240f8b9463e8acfd37a1 and included in > Linux v3.8-rc2 and later. Linux 3.7.3, 3.4.26, 3.2.37, 3.0.59 all have this fix already. Linux 3.5.7.3 will also have this. > This fix will likely be backported to stable and vendor kernels, > so we'll whitelist them as we learn of them. I've reverted this workaround (and pushed to master @ git://bogomips.org/sleepy_penguin.git ) commit b3fa14976bc41c2daad0b8a6afd74a8212dcb97b Author: Eric Wong Date: Thu Jan 17 21:30:30 2013 +0000 Revert "epoll: avoid EPOLL_CTL_MOD race condition" This reverts commit 02e5a91b24983d96b342c007661966495ccdb619. This workaround may have unintended side-effects for apps using EPOLL_CTL_DEL. -- Eric Wong