From patchwork Mon Jun 8 10:06:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?TWljaGHFgiBNaXJvc8WCYXc=?= X-Patchwork-Id: 11593015 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D2A5E913 for ; Mon, 8 Jun 2020 10:07:33 +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 ACC27206D5 for ; Mon, 8 Jun 2020 10:07:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="sQLg7Tbu"; dkim=pass (2048-bit key) header.d=rere.qmqm.pl header.i=@rere.qmqm.pl header.b="AND0CpYe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ACC27206D5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=rere.qmqm.pl 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 D8BD315E4; Mon, 8 Jun 2020 12:06:42 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz D8BD315E4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1591610850; bh=CDrLC2kySs5OBNJvqoPu46VZEBqI3bBc1GI8m0d56kY=; h=Date:In-Reply-To:References:From:Subject:To:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=sQLg7TbuLn6JJBBNAIWKlcVjP/KRnSYN/2fTaM9nMda1HD1sVHuUghpP5FyNEbd6U k9j4ZDBI5zcbSo5nQvyadEJ4FjWms16ZT/b602RtFAg5aXCCv/FZQZoQ8X/wcehFph HfCHX/r2KGKiacv7SydaS+7xH+g99dok9xZdMN1w= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 5A549F801F7; Mon, 8 Jun 2020 12:06:42 +0200 (CEST) X-Original-To: alsa-devel@alsa-project.org Delivered-To: alsa-devel@alsa-project.org Received: by alsa1.perex.cz (Postfix, from userid 50401) id 72E02F8024A; Mon, 8 Jun 2020 12:06:40 +0200 (CEST) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on alsa1.perex.cz X-Spam-Level: X-Spam-Status: No, score=-0.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,SPF_HELO_PASS,SPF_PASS,URIBL_BLOCKED autolearn=disabled version=3.4.0 Received: from rere.qmqm.pl (rere.qmqm.pl [91.227.64.183]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 793FEF801F7 for ; Mon, 8 Jun 2020 12:06:33 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 793FEF801F7 Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key) header.d=rere.qmqm.pl header.i=@rere.qmqm.pl header.b="AND0CpYe" Received: from remote.user (localhost [127.0.0.1]) by rere.qmqm.pl (Postfix) with ESMTPSA id 49gTRs19bxzY4; Mon, 8 Jun 2020 12:06:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=rere.qmqm.pl; s=1; t=1591610793; bh=CDrLC2kySs5OBNJvqoPu46VZEBqI3bBc1GI8m0d56kY=; h=Date:In-Reply-To:References:From:Subject:To:Cc:From; b=AND0CpYeEW677MDFgvTIx8zReIBMkD6olRKBzvkZOdeyRXBwmQTvOWiGG/iBeA7BS yX8DP+UguZnDbIuxjkyajal9FqWaBgxqph/knGrmulPBWffp38IYQXNa+8Eyrs2QOT NiAbq3Jsu+A9w3670L59ZP33sK2Y5CnpiPZoXyAvuu7GA6GsqC2v8qltNdO1cKlkzr bKsQ2v33ERBu5+zVjsyp6hZpSvWcgm4Y5pfZ3Z0EfC2ez9HSTQWz+dlBAfx0wsfHGb a401+jf5+fn4MHv3268WB6TYdDLlI5e07znuu+kblHpbo7wWoBxUFw9sPNHXyvC948 w4BOzftnZDgNQ== X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.102.2 at mail Date: Mon, 08 Jun 2020 12:06:32 +0200 Message-Id: <37252c65941e58473b1219ca9fab03d48f47e3e3.1591610330.git.mirq-linux@rere.qmqm.pl> In-Reply-To: References: From: =?utf-8?b?TWljaGHFgiBNaXJvc8WCYXc=?= Subject: [PATCH 2/2] ALSA: pcm: fix snd_pcm_link() lockdep splat MIME-Version: 1.0 To: Jaroslav Kysela , Takashi Iwai Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org 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" Add and use snd_pcm_stream_lock_nested() in snd_pcm_link/unlink implementation. The code is fine, but generates a lockdep complaint: ============================================ WARNING: possible recursive locking detected 5.7.1mq+ #381 Tainted: G O -------------------------------------------- pulseaudio/4180 is trying to acquire lock: ffff888402d6f508 (&group->lock){-...}-{2:2}, at: snd_pcm_common_ioctl+0xda8/0xee0 [snd_pcm] but task is already holding lock: ffff8883f7a8cf18 (&group->lock){-...}-{2:2}, at: snd_pcm_common_ioctl+0xe4e/0xee0 [snd_pcm] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&group->lock); lock(&group->lock); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by pulseaudio/4180: #0: ffffffffa1a05190 (snd_pcm_link_rwsem){++++}-{3:3}, at: snd_pcm_common_ioctl+0xca0/0xee0 [snd_pcm] #1: ffff8883f7a8cf18 (&group->lock){-...}-{2:2}, at: snd_pcm_common_ioctl+0xe4e/0xee0 [snd_pcm] [...] Cc: stable@vger.kernel.org Fixes: f57f3df03a8e ("ALSA: pcm: More fine-grained PCM link locking") Signed-off-by: Michał Mirosław --- sound/core/pcm_native.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index 3ad399cb6f30..5b36881f7095 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -138,6 +138,16 @@ void snd_pcm_stream_lock_irq(struct snd_pcm_substream *substream) } EXPORT_SYMBOL_GPL(snd_pcm_stream_lock_irq); +static void snd_pcm_stream_lock_nested(struct snd_pcm_substream *substream) +{ + struct snd_pcm_group *group = &substream->self_group; + + if (substream->pcm->nonatomic) + mutex_lock_nested(&group->mutex, SINGLE_DEPTH_NESTING); + else + spin_lock_nested(&group->lock, SINGLE_DEPTH_NESTING); +} + /** * snd_pcm_stream_unlock_irq - Unlock the PCM stream * @substream: PCM substream @@ -2200,7 +2210,7 @@ static int snd_pcm_link(struct snd_pcm_substream *substream, int fd) snd_pcm_stream_unlock_irq(substream); snd_pcm_group_lock_irq(target_group, nonatomic); - snd_pcm_stream_lock(substream1); + snd_pcm_stream_lock_nested(substream1); snd_pcm_group_assign(substream1, target_group); refcount_inc(&target_group->refs); snd_pcm_stream_unlock(substream1); @@ -2216,7 +2226,7 @@ static int snd_pcm_link(struct snd_pcm_substream *substream, int fd) static void relink_to_local(struct snd_pcm_substream *substream) { - snd_pcm_stream_lock(substream); + snd_pcm_stream_lock_nested(substream); snd_pcm_group_assign(substream, &substream->self_group); snd_pcm_stream_unlock(substream); }