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=-3.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 A30D9C433E0 for ; Mon, 8 Jun 2020 12:49:48 +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 2E5812072F for ; Mon, 8 Jun 2020 12:49:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="MCifjfCQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E5812072F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de 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 94F2315E4; Mon, 8 Jun 2020 14:48:56 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 94F2315E4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1591620586; bh=UMGzkwt02Lc6cwgyVYm8EbAEubvUOSkGEH0a8C9W8P4=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=MCifjfCQlFJgfYtWmt3iDXPLiLolDnzMVQnQavS1ysJh2f6ZajRbccpITZPTawuqA Q6Nev3B1fmZlU7pdSg6l9RnssMG/rLhY4UGOYrSsiSmGAU8IBL9MyAJM2trXQKCEam 0wu17OeADa8KbqHBZESjBjPwJmzP9NZHSNF7tdj4= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 4313DF8021E; Mon, 8 Jun 2020 14:48:56 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 52DFFF8024A; Mon, 8 Jun 2020 14:48:55 +0200 (CEST) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id F307EF80125 for ; Mon, 8 Jun 2020 14:48:41 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz F307EF80125 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 24660AD7D; Mon, 8 Jun 2020 12:48:44 +0000 (UTC) Date: Mon, 08 Jun 2020 14:48:40 +0200 Message-ID: From: Takashi Iwai To: =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= Subject: Re: [PATCH 1/2] ALSA: pcm: disallow linking stream to itself In-Reply-To: References: User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org, Takashi Iwai 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" On Mon, 08 Jun 2020 12:06:32 +0200, Michał Mirosław wrote: > > Prevent SNDRV_PCM_IOCTL_LINK linking stream to itself - the code > can't handle it. Fixed commit is not where bug was introduced, but > changes the context significantly. > > Cc: stable@vger.kernel.org > Fixes: 0888c321de70 ("pcm_native: switch to fdget()/fdput()") > Signed-off-by: Michał Mirosław Thanks for the fix. Just a minor point: > @@ -2166,6 +2166,12 @@ static int snd_pcm_link(struct snd_pcm_substream *substream, int fd) > } > pcm_file = f.file->private_data; > substream1 = pcm_file->substream; > + > + if (substream == substream1) { > + res = -EDEADLK; We've never used this error code, hence it may confuse the user-space side. I'd use a more standard -EINVAL instead; the error is basically an invalid argument, after all. thanks, Takashi