From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f51.google.com (mail-dl1-f51.google.com [74.125.82.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 83566391827 for ; Fri, 27 Mar 2026 12:28:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774614522; cv=none; b=cOBZ2Ie0K1GdPRwXIZg+vrZ2wPVv326SD9ii1Zi2rsugcMhQ3aX+A30KAlXBxiDyME29xwckBl+UNBr3eE3LhEUs5ePz3OHkPM2mTLnbea9pB1P0LalNRHWaF9RpRp/IAGRCQjJOavl89mRaFZISkDkRwGKBAP91hIkTdl/6CVI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774614522; c=relaxed/simple; bh=/GQREby2l5g/PuAOH0xjt7pPxN1b/Y0J7Sacx3VEIUM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=LzluR3shmU28PSFo27F2bChI45nJZhKsDmr458Aemu2UCUeVDsYYCh036GqIILVN9TzJrC3MBj4hFwTfiGtZqc7TP+3cDyPy31Y0XU3ec+d0MhSqanXI9JyJKiw5ovT78T9yFTcrHw7XWHH2OIOvCWF2qTTweSPWyFxPGiyRlEc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=fLlaC+iE; arc=none smtp.client-ip=74.125.82.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="fLlaC+iE" Received: by mail-dl1-f51.google.com with SMTP id a92af1059eb24-128b9b7e3edso927604c88.0 for ; Fri, 27 Mar 2026 05:28:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1774614521; x=1775219321; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:content-language:from :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=qgGKHRXHvxgAbIuqYwH/wwAlALbdgjHZfUyg8uIlkB8=; b=fLlaC+iE7kLj1uT+pokkjP+OtLWQUer7TIhnhaadHyPIJdE/LyQYRjvX23Tlxc/P8K 6E9nRsMah17KSCVWRezsLPeg4q1tsgH/AaYRYXY8/0pP10DNu4TVqE6u6pthdQISi7tu pCetzT0sqeOX3tMCVq3q2p5AMgxTVyL09a8pYc8W5HqsBjH6omDKq8ohnPPnkiRdT8U5 ojpQ2MjyFyF+QNeO/Sozwa4xECCLHhbQDgKlvms22O6ub7hvnePH9xwoFzPmI7M35lrQ g16vgW62NxPo9hg9TtLSny5eRhh02vb+dgwEzEFJ1PivyPA7mwB2LEa8nag7ZodVZQsv Tnrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774614521; x=1775219321; h=content-transfer-encoding:in-reply-to:content-language:from :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=qgGKHRXHvxgAbIuqYwH/wwAlALbdgjHZfUyg8uIlkB8=; b=W4pmzkJlKGGB3uMsEFet6gn9YKJ/CyvPdml3Pu5rGcN4WHRzQQKC0u3+VIIZxvXa+T z+Q5A3GA3es1dbir6K5yuf8XhbvD30YV9tJGMClKvv39rLQE6GDKnjZGX361z6oWIZ2c ikTHTHqS6xgANUbYcNFDa5JmHKEa1KD3bSx1apCpFSJiNi7OFCWTsmGY/JcAmegz49yV fcI1gN8tWvzdaMdlmNoNg4XVIlwq1DOwu9C2khBX/g+e8qcp8gvMr+TQJnw6zegFiLh3 x4KSdGVF/vy0QgzDVrjKaGybZwixODGTb+HqG+5BEC1Ijds+IhzA/Q7zL7tc4F7FkT/3 hAEA== X-Forwarded-Encrypted: i=1; AJvYcCVqqNdllBHl8+82/VgmHWh722JZ0hRw225mP/wGMUQmV1RXNLE3JItqs4NJ7ioQr5nlu+Ss99wM4UcKFqA=@vger.kernel.org X-Gm-Message-State: AOJu0YwHsiqb5fBM2+UPM5+8A6xhoslbKVnQmh3KNC0Ngr8zVWY00kyz +Dxn0X4SlkysZU6gyY+JkCEy3IjPXPmmgJNn1I+trZuvgE56qShZFO+b X-Gm-Gg: ATEYQzy7EnoIjnyhjsUONo/VaY7tkdMMuaYzgcf83Gg7WETq8txMCSV3xZJ42X2eW4q cfU9YSdCdYT91lsuy+6r6lcOYIN0QhBn25p7rfTysi7pkW7sLtsLsdbSsv1W/07CW3yd5nfNclp 9ysRGESqJQu6ams/trD4RPR0LtFlVTExB936AeGgNoOvaROYe5VBPR9dmJjr866aznBlfMbZHnR +Zt9ElUJD9OcS2038aadCNi8FlXd9SKr/4EZyDINL3/GLKmAbXnRUNz/3QkksNAT3apQjSsxp2s 3FOar9w1UbWhlan6Jht4oTBZlUtBelg6XL8ybqp2RXgIlQJZzk6qEBEL/u30WCmu+UmTJaYj0iK BknZ6ez434fhZy9fxBtgn+rViBu8s8zBfxv5I6oTt2JRg08HCouMjeiA0YhF7yIm6e4vIBkom+i 25Rr/3XLUYoUTY2hocTEOnKr4ty94ROGlxD7ECRnxb7dlpxEzaE4yTIJiD7EzXx0FuZXUcX8z/ X-Received: by 2002:a05:7022:4589:b0:11b:ec5f:1c37 with SMTP id a92af1059eb24-12ab28d5ce5mr1422992c88.18.1774614520473; Fri, 27 Mar 2026 05:28:40 -0700 (PDT) Received: from [192.168.1.8] (177-4-161-78.user3p.v-tal.net.br. [177.4.161.78]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-12aa762430bsm7686697c88.10.2026.03.27.05.28.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 27 Mar 2026 05:28:40 -0700 (PDT) Message-ID: <598871fe-b82e-4d51-9886-8c16dc68ed6a@gmail.com> Date: Fri, 27 Mar 2026 09:28:36 -0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] ALSA: pcm: Serialize snd_pcm_suspend_all() with open_mutex To: Takashi Iwai Cc: Takashi Iwai , Jaroslav Kysela , linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260320-alsa-pcm-suspend-open-close-lock-v1-1-b5992a120335@gmail.com> <87se9lqz8k.wl-tiwai@suse.de> From: =?UTF-8?Q?C=C3=A1ssio_Gabriel_Monteiro_Pires?= Content-Language: en-US In-Reply-To: <87se9lqz8k.wl-tiwai@suse.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 3/27/26 08:38, Takashi Iwai wrote: >> walks all PCM substreams and uses a lockless >> runtime check to skip closed streams. It then calls snd_pcm_suspend() >> for each remaining substream and finally runs snd_pcm_sync_stop() in a >> second pass. >> >> The runtime lifetime is still controlled by pcm->open_mutex in the >> open/release path. That means a concurrent close can clear or free >> substream->runtime after the initial check in snd_pcm_suspend_all(), >> leaving the later suspend or sync-stop path to dereference a stale or >> NULL runtime pointer. >> >> Serialize snd_pcm_suspend_all() with pcm->open_mutex so the runtime >> pointer stays stable across both loops. This matches the existing PCM >> runtime lifetime rule already used by other core paths that access >> substream->runtime outside the stream lock. >> >> Signed-off-by: Cássio Gabriel > I guess it's safe to take open_mutex from this function, but it's > still worth to mention it in the function description. > Could you update the description of snd_pcm_suspend_all(), too? > Yes, I'll do it and send the v2 patch. -- Thanks, Cássio