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=-7.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 C1F04C433FE for ; Fri, 11 Dec 2020 17:22:00 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 00D4A23DC2 for ; Fri, 11 Dec 2020 17:21:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 00D4A23DC2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=perex.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 1E9C7170C; Fri, 11 Dec 2020 18:21:07 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 1E9C7170C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1607707317; bh=f7mHP5sylKi1coueGxI4SHx6LgnK4emI00bPJF5+CdM=; h=Subject:To:References:From:Date:In-Reply-To:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=W5VgWZSlrAZzAV/lRgX/luMunuDE3lFylY7ICaWb53BcaWYFcTdc5PBjdYgfCx91X T99jsrKj/ztDSHJlGVUf69IojBcXQKkLILPkJrURqz2h+dWBT2Nxf5nVOlkiPfUZXT U6diYI7fJ1Lfcglct7O9jarizVVCOash9fpy+TjM= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id A8E6DF80105; Fri, 11 Dec 2020 18:21:06 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 30C36F8020D; Fri, 11 Dec 2020 18:21:05 +0100 (CET) Received: from mail1.perex.cz (mail1.perex.cz [77.48.224.245]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 1536EF80105 for ; Fri, 11 Dec 2020 18:20:53 +0100 (CET) Received: from mail1.perex.cz (localhost [127.0.0.1]) by smtp1.perex.cz (Perex's E-mail Delivery System) with ESMTP id F2DB8A0040; Fri, 11 Dec 2020 18:20:52 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.perex.cz F2DB8A0040 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=perex.cz; s=default; t=1607707253; bh=fsDD+oO7MjQoATGLa4HiZNVuQFUx4PCtGM8mkR5L8fM=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=lm7Ldv6eBN9F3NL/+5NJ9/c3C+EsZlvqgEfaLXUs9h8RxAslMrfFt/vm1lsaTQNxO iiwJBgLIgkBGcJ3EePYmrm8I64jlZ0nbFeY73QINZnkIopX6uh7Solcx+qYe6rb7ul Sgt9jNMEBluqTdRv55fFcd0Ko90qAU6Io1kuye28= Received: from p1gen2.perex-int.cz (unknown [192.168.100.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: perex) by mail1.perex.cz (Perex's E-mail Delivery System) with ESMTPSA; Fri, 11 Dec 2020 18:20:50 +0100 (CET) Subject: Re: [PATCH] alsactl: Skip restore during the lock To: Takashi Iwai References: <20201211083804.800-1-tiwai@suse.de> From: Jaroslav Kysela Message-ID: Date: Fri, 11 Dec 2020 18:20:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Cc: ALSA development X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" Dne 11. 12. 20 v 17:59 Takashi Iwai napsal(a): > On Fri, 11 Dec 2020 17:45:45 +0100, > Jaroslav Kysela wrote: >> >> Dne 11. 12. 20 v 9:38 Takashi Iwai napsal(a): >>> Currently alsactl-restore tries to initialize the device when an error >>> is found for restore action. But this isn't the right behavior in the >>> case where the lock is held; it implies that another alsactl is >>> running concurrently, hence you shouldn't initialize the card at the >>> same time. The situation is found easily when two alsactls get >>> started by both udev and systemd (note that those two invocations are >>> the designed behavior, see /usr/lib/udev/rules.d/78-sound-cards.rules >>> for details). >>> >>> This patch changes load_state() not to handle the initialization if >>> the locking fails. >> >> The operation should serialize in this case (there's limit of 10 seconds which >> should be enough to finish the initialization). The state_lock() function >> should return -EBUSY when the file is locked (and I'm fine to change the >> behaviour from 'init' to 'skip' for this lock state). >> >> It seems that -EEXIST is returned when the lock file exists, but the >> open(file, O_CREAT|O_EXCL, 0644) caller has not enough priviledges to access >> this file when another user owns the file. >> >> But alsactl from /lib/udev/rules.d/90-alsa-restore.rules and >> /lib/systemd/system/alsa-restore.service should be run as root, right? > > Yes, it should be root. > > I also wondered how EEXIST comes, too. Maybe it's also the race > between the first open(O_RDWR) and the second > open(O_RDWR|O_CREAT|O_EXCL)? If so, it'd be better to go back again > to the normal open(O_RDWR)? Maybe. It seems enough to add EEXIST errno check to the "if (errno == EBUSY || errno == EAGAIN)" condition to repeat the open sequence. The -EBUSY will be returned correctly then. The one second delay is harmless in my eyes for the second task. Jaroslav -- Jaroslav Kysela Linux Sound Maintainer; ALSA Project; Red Hat, Inc.