From owner-svn-src-all@FreeBSD.ORG Mon Apr 12 14:33:58 2010 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 923E6106564A; Mon, 12 Apr 2010 14:33:58 +0000 (UTC) (envelope-from rpaulo@gmail.com) Received: from mail-ew0-f224.google.com (mail-ew0-f224.google.com [209.85.219.224]) by mx1.freebsd.org (Postfix) with ESMTP id B6DCE8FC28; Mon, 12 Apr 2010 14:33:57 +0000 (UTC) Received: by ewy24 with SMTP id 24so968512ewy.33 for ; Mon, 12 Apr 2010 07:33:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:subject:mime-version :content-type:from:in-reply-to:date:cc:content-transfer-encoding :message-id:references:to:x-mailer; bh=Op6WhIDdIyb1Zq/CCiBOqDpZhj+7nObfTB8H/C2325s=; b=cwyGTvJ99b052O+9PZit2LkzkW+F/Ie7tLSeIIiLwA5Hn2nlYuqKPkqkbJP9Ks/MuR cccohOE03E3u1XP3+0/iLoTA6edHTLqngbak3d3K9kdLzpnToBv+x7wWD84iyg8UxJQB UBnRCud2Cg9uY/gcHIzqjRyHz3+5Loro6zayk= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:subject:mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to:x-mailer; b=FtJtRFfU20sY+KiMaUuz4+Sc+S1QTKROOKxaNplH/ZP5PDHvG64G+c9k70qql5faC6 a+Yj7NQYiJaK7nu/+/gQAzyBYt4kehJged0bdWVEE2vqmSSsUHGhYLGFHBhl3Mf2Um9s kF7tqDqabwReMuPIxnRzfuy9Y/B2cf4QcWUjg= Received: by 10.103.81.12 with SMTP id i12mr2058662mul.89.1271082836420; Mon, 12 Apr 2010 07:33:56 -0700 (PDT) Received: from [10.0.10.2] (54.81.54.77.rev.vodafone.pt [77.54.81.54]) by mx.google.com with ESMTPS id j10sm17587345mue.18.2010.04.12.07.33.54 (version=TLSv1/SSLv3 cipher=RC4-MD5); Mon, 12 Apr 2010 07:33:54 -0700 (PDT) Sender: Rui Paulo Mime-Version: 1.0 (Apple Message framework v1078) Content-Type: text/plain; charset=us-ascii From: Rui Paulo In-Reply-To: <4BC250CF.30600@errno.com> Date: Mon, 12 Apr 2010 15:33:52 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: <256D847F-E64D-4802-8266-C2AC4DCDFF72@FreeBSD.org> References: <201004091206.o39C6JBo046371@svn.freebsd.org> <4BC250CF.30600@errno.com> To: Sam Leffler X-Mailer: Apple Mail (2.1078) Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r206419 - head/sys/net80211 X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 Apr 2010 14:33:58 -0000 On 11 Apr 2010, at 23:44, Sam Leffler wrote: > Rui Paulo wrote: >> Author: rpaulo >> Date: Fri Apr 9 12:06:19 2010 >> New Revision: 206419 >> URL: http://svn.freebsd.org/changeset/base/206419 >> Log: >> Use M_NOWAIT instead of M_WAITOK to avoid race conditions. >> =20 >=20 > Can you describe these race conditions (or at least one of them)? Some drivers call ratectl functions with locks held. I saw similar = allocations in the net80211 stack that used M_NOWAIT and printed an = error if the allocation failed, but didn't notify the caller (for = example ieee80211_node_table_init()). If I use M_WAITOK here I'll also get WITNESS warnings. Regards, -- Rui Paulo