From patchwork Fri Mar 17 19:51:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Keeping X-Patchwork-Id: 13179396 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id D9ED9C74A5B for ; Fri, 17 Mar 2023 19:52:59 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 14CCFEDB; Fri, 17 Mar 2023 20:52:07 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 14CCFEDB DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1679082777; bh=cKDRB7kk2YGr7OBXD2Zsehi7mROsyMrgQGyl8pjX/bA=; h=From:To:Subject:Date:CC:List-Id:List-Archive:List-Help:List-Owner: List-Post:List-Subscribe:List-Unsubscribe:From; b=fX4E9cvqZXSztWfjjmfJZxMDARMSXeoQ3zHXqQNWtyuZBmAFlghg+4Z7IpM0QdJCW HS9atfKBj4R97qu7LH6/1zqoKmFT7yK80uCHR9lCKD3nfCcENt/D/c+fKXs7J4CLJH Kuvm23gTG2Bx2c8q64VZykw8DS+2eVi6zFAkLJa0= Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id 46938F800C9; Fri, 17 Mar 2023 20:51:45 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 32BFEF80423; Fri, 17 Mar 2023 20:51:40 +0100 (CET) Received: from metanate.com (unknown [IPv6:2001:8b0:1628:5005::111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id C33FAF80272 for ; Fri, 17 Mar 2023 20:51:37 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz C33FAF80272 Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key, unprotected) header.d=metanate.com header.i=@metanate.com header.a=rsa-sha256 header.s=stronger header.b=BjfN6g0P DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=metanate.com; s=stronger; h=Content-Transfer-Encoding:Message-Id:Date: Subject:Cc:To:From:Content-Type:Reply-To:Content-ID:Content-Description: In-Reply-To:References; bh=WMRMW29s9nOaMfP2biYXwZDcUwXYbo2yYgouF2jc1Vo=; b=Bj fN6g0PhfTM4vzqmTfbkfbg7O0909IYYyF09Boh7IFtKJobke6zESAOEhA6gRjUiFH7S/8rbFCoWGh TCzSRlJBE0w24cuZ6M6KhIulMJ22fm9yn2vSCnouEci+r2Ugkp8YFH+1dlpPlobg6BDnomta6su5X z7TyexeNpIklJ/vXXbQLQ7CmTTGDFN2zSH3gTkFUjluvobjMmW5RV74QRcCWC77O2OHGNwuR6t6MA +lQ/SH10NAHsfnOWVFFGYYYYf52/499AiwqMcW/eKTgcrpKQvegvJ8cNB+b+caI+WxoOigmzItrGk xKle75lA8JZJetsHLviWyNjXQO+3rHWw==; Received: from [81.174.171.191] (helo=donbot.metanate.com) by email.metanate.com with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1pdG6u-00008O-4s; Fri, 17 Mar 2023 19:51:33 +0000 From: John Keeping To: Takashi Iwai Subject: [PATCH] ALSA: usb-audio: Fix recursive locking on XRUN Date: Fri, 17 Mar 2023 19:51:27 +0000 Message-Id: <20230317195128.3911155-1-john@metanate.com> X-Mailer: git-send-email 2.40.0 MIME-Version: 1.0 X-Authenticated: YES Message-ID-Hash: C6K7EZ4URF4XASUU7FEB7FBNIU7POB6C X-Message-ID-Hash: C6K7EZ4URF4XASUU7FEB7FBNIU7POB6C X-MailFrom: john@metanate.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: John Keeping , "moderated list:SOUND" , open list X-Mailman-Version: 3.3.8 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: snd_usb_queue_pending_output_urbs() may be called from snd_pcm_ops::ack() which means the PCM stream is locked. For the normal case where the call back into the PCM core is via prepare_output_urb() the "_under_stream_lock" variant of snd_pcm_period_elapsed() is called, but when an error occurs and the stream is stopped as XRUN then snd_pcm_xrun() tries to recursively lock the stream which results in deadlock. Follow the example of snd_pcm_period_elapsed() by adding snd_pcm_xrun_under_stream_lock() and use this when the PCM substream lock is already held. Signed-off-by: John Keeping Tested-by: John Keeping --- include/sound/pcm.h | 1 + sound/core/pcm_native.c | 28 ++++++++++++++++++++++++---- sound/usb/endpoint.c | 18 +++++++++++------- 3 files changed, 36 insertions(+), 11 deletions(-) diff --git a/include/sound/pcm.h b/include/sound/pcm.h index 27040b472a4f..98551907453a 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -571,6 +571,7 @@ int snd_pcm_status64(struct snd_pcm_substream *substream, int snd_pcm_start(struct snd_pcm_substream *substream); int snd_pcm_stop(struct snd_pcm_substream *substream, snd_pcm_state_t status); int snd_pcm_drain_done(struct snd_pcm_substream *substream); +int snd_pcm_stop_xrun_under_stream_lock(struct snd_pcm_substream *substream); int snd_pcm_stop_xrun(struct snd_pcm_substream *substream); #ifdef CONFIG_PM int snd_pcm_suspend_all(struct snd_pcm *pcm); diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index 331380c2438b..617f5dc74df0 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -1559,24 +1559,44 @@ int snd_pcm_drain_done(struct snd_pcm_substream *substream) SNDRV_PCM_STATE_SETUP); } +/** + * snd_pcm_stop_xrun_under_stream_lock - stop the running stream as XRUN under the lock of + * the PCM substream. + * @substream: the PCM substream instance + * + * This stops the given running substream (and all linked substreams) as XRUN. + * This function assumes that the substream lock is already held. + * + * Return: Zero if successful, or a negative error core. + */ +int snd_pcm_stop_xrun_under_stream_lock(struct snd_pcm_substream *substream) +{ + if (substream->runtime && snd_pcm_running(substream)) + __snd_pcm_xrun(substream); + + return 0; +} + /** * snd_pcm_stop_xrun - stop the running streams as XRUN * @substream: the PCM substream instance * + * This function is similar to ``snd_pcm_stop_xrun_under_stream_lock()`` except that it + * acquires the substream lock itself. + * * This stops the given running substream (and all linked substreams) as XRUN. - * Unlike snd_pcm_stop(), this function takes the substream lock by itself. * * Return: Zero if successful, or a negative error code. */ int snd_pcm_stop_xrun(struct snd_pcm_substream *substream) { unsigned long flags; + int ret; snd_pcm_stream_lock_irqsave(substream, flags); - if (substream->runtime && snd_pcm_running(substream)) - __snd_pcm_xrun(substream); + ret = snd_pcm_stop_xrun_under_stream_lock(substream); snd_pcm_stream_unlock_irqrestore(substream, flags); - return 0; + return ret; } EXPORT_SYMBOL_GPL(snd_pcm_stop_xrun); diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index 1e0af1179ca8..83a6b6d41374 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -400,13 +400,17 @@ static int prepare_inbound_urb(struct snd_usb_endpoint *ep, } /* notify an error as XRUN to the assigned PCM data substream */ -static void notify_xrun(struct snd_usb_endpoint *ep) +static void notify_xrun(struct snd_usb_endpoint *ep, bool in_stream_lock) { struct snd_usb_substream *data_subs; data_subs = READ_ONCE(ep->data_subs); - if (data_subs && data_subs->pcm_substream) - snd_pcm_stop_xrun(data_subs->pcm_substream); + if (data_subs && data_subs->pcm_substream) { + if (in_stream_lock) + snd_pcm_stop_xrun_under_stream_lock(data_subs->pcm_substream); + else + snd_pcm_stop_xrun(data_subs->pcm_substream); + } } static struct snd_usb_packet_info * @@ -498,7 +502,7 @@ void snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep, if (err == -EAGAIN) push_back_to_ready_list(ep, ctx); else - notify_xrun(ep); + notify_xrun(ep, in_stream_lock); return; } @@ -507,7 +511,7 @@ void snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep, usb_audio_err(ep->chip, "Unable to submit urb #%d: %d at %s\n", ctx->index, err, __func__); - notify_xrun(ep); + notify_xrun(ep, in_stream_lock); return; } @@ -574,7 +578,7 @@ static void snd_complete_urb(struct urb *urb) return; usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err); - notify_xrun(ep); + notify_xrun(ep, false); exit_clear: clear_bit(ctx->index, &ep->active_mask); @@ -1762,7 +1766,7 @@ static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep, usb_audio_err(ep->chip, "next package FIFO overflow EP 0x%x\n", ep->ep_num); - notify_xrun(ep); + notify_xrun(ep, false); return; }