From nobody Thu Dec 18 20:35:34 2025 Received: from mail-41104.protonmail.ch (mail-41104.protonmail.ch [185.70.41.104]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E7E5578C98 for ; Mon, 29 Jul 2024 21:51:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.70.41.104 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722289909; cv=none; b=GKEAUdd+b+AQcQP724evKh9M4KCTMXN7Fp2iR+p4EArJiLOEBQqJDdmqeUWsDrlQTO3tFuw7e+Ef56HUmXQBBnZx1Bnc1MGthnEQgA078+B+XJdyTK2FZL5DQETYB2OiM04ef54NvF3MlVmb/onLVGY1XDbuSWPNaHXcAB/L5oM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722289909; c=relaxed/simple; bh=jC/KhaJqTmeXOybIabumropkSzYE0inJWgtzdauR0uY=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=mJqYx7JjhArpy+qREZtQdVAowPvmX1beXJvK1TTT5p+McE0OznLcLvF+vo4LM4F5y3gnFN/iIqideSF7oOmBnHHp2HdHnMGWZHaUbVlect0c1czvI6uiO1DLCbK5HY65fQpVWs/eZwd6hQ33wu1TPbLg70OPdQeFxOnRfzz7vC4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=protonmail.com; spf=pass smtp.mailfrom=protonmail.com; dkim=pass (2048-bit key) header.d=protonmail.com header.i=@protonmail.com header.b=PGAhNV8+; arc=none smtp.client-ip=185.70.41.104 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=protonmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=protonmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=protonmail.com header.i=@protonmail.com header.b="PGAhNV8+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1722289336; x=1722548536; bh=0qv70E0VnYWx518cQ856tZOi8XtGafmVVQLWE08yAXM=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=PGAhNV8+QoY6wSrpGHnI0EmFTa50atee4UlSqQYnGlrBHiYPtWG1/ynQXWj3D8K9t TaasUrFwsuLg0nj7420s5KCYUFV3GqpBK7QrI20CbToKBxW7BpVAw78ccMY9TT7Caq Y7iLTeiLeSLeokU8gCsxlel+Rwbv/UeRodI/kYOjbDI49heKGzClgaLpsmKJp4Q6m/ k3aQJIuuVrBbYnx9lxU7wQ0Eoei0dJoZkPZKjLCUCrPPpkrZIDu1pBjKENutufch+x Rv3iI3f+3PgV8xf6MKLy/VjkTCh7i3WLQDb1QwEBsyRohKXVezFQ5L8DMz8JEVGeQa 4WA3U/XBP2hmw== Date: Mon, 29 Jul 2024 21:42:11 +0000 To: o-takashi@sakamocchi.jp, clemens@ladisch.de From: Edmund Raile Cc: tiwai@suse.com, alsa-devel@alsa-project.org, linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v3 1/3] Revert "ALSA: firewire-lib: obsolete workqueue for period update" Message-ID: <20240729214149.752663-2-edmund.raile@protonmail.com> In-Reply-To: <20240729214149.752663-1-edmund.raile@protonmail.com> References: <20240729214149.752663-1-edmund.raile@protonmail.com> Feedback-ID: 43016623:user:proton X-Pm-Message-ID: ef79e849b7a2927f46f7a6f6a07e5d260af1f69f Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" prepare resolution of AB/BA deadlock competition for substream lock: restore workqueue previously used for process context: revert commit b5b519965c4c ("ALSA: firewire-lib: obsolete workqueue for period update") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hze= o4simnl@jn3eo7pe642q/ Signed-off-by: Edmund Raile --- sound/firewire/amdtp-stream.c | 15 +++++++++++++++ sound/firewire/amdtp-stream.h | 1 + 2 files changed, 16 insertions(+) diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index d35d0a420ee0..31201d506a21 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -77,6 +77,8 @@ // overrun. Actual device can skip more, then this module stops the packet= streaming. #define IR_JUMBO_PAYLOAD_MAX_SKIP_CYCLES 5 =20 +static void pcm_period_work(struct work_struct *work); + /** * amdtp_stream_init - initialize an AMDTP stream structure * @s: the AMDTP stream to initialize @@ -105,6 +107,7 @@ int amdtp_stream_init(struct amdtp_stream *s, struct fw= _unit *unit, s->flags =3D flags; s->context =3D ERR_PTR(-1); mutex_init(&s->mutex); + INIT_WORK(&s->period_work, pcm_period_work); s->packet_index =3D 0; =20 init_waitqueue_head(&s->ready_wait); @@ -347,6 +350,7 @@ EXPORT_SYMBOL(amdtp_stream_get_max_payload); */ void amdtp_stream_pcm_prepare(struct amdtp_stream *s) { + cancel_work_sync(&s->period_work); s->pcm_buffer_pointer =3D 0; s->pcm_period_pointer =3D 0; } @@ -624,6 +628,16 @@ static void update_pcm_pointers(struct amdtp_stream *s, } } =20 +static void pcm_period_work(struct work_struct *work) +{ + struct amdtp_stream *s =3D container_of(work, struct amdtp_stream, + period_work); + struct snd_pcm_substream *pcm =3D READ_ONCE(s->pcm); + + if (pcm) + snd_pcm_period_elapsed(pcm); +} + static int queue_packet(struct amdtp_stream *s, struct fw_iso_packet *para= ms, bool sched_irq) { @@ -1910,6 +1924,7 @@ static void amdtp_stream_stop(struct amdtp_stream *s) return; } =20 + cancel_work_sync(&s->period_work); fw_iso_context_stop(s->context); fw_iso_context_destroy(s->context); s->context =3D ERR_PTR(-1); diff --git a/sound/firewire/amdtp-stream.h b/sound/firewire/amdtp-stream.h index a1ed2e80f91a..775db3fc4959 100644 --- a/sound/firewire/amdtp-stream.h +++ b/sound/firewire/amdtp-stream.h @@ -191,5 +191,6 @@ struct amdtp_stream { =20 /* For a PCM substream processing. */ struct snd_pcm_substream *pcm; + struct work_struct period_work; snd_pcm_uframes_t pcm_buffer_pointer; unsigned int pcm_period_pointer; --=20 2.45.2 From nobody Thu Dec 18 20:35:34 2025 Received: from mail-40137.protonmail.ch (mail-40137.protonmail.ch [185.70.40.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D4CE818E77E for ; 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charset="utf-8" Commit 7ba5ca32fe6e ("ALSA: firewire-lib: operate for period elapse event in process context") removed the process context workqueue from amdtp_domain_stream_pcm_pointer() and update_pcm_pointers() to remove its overhead. With RME Fireface 800, this lead to a regression since Kernels 5.14.0, causing an AB/BA deadlock competition for the substream lock with eventual system freeze under ALSA operation: thread 0: * (lock A) acquire substream lock by snd_pcm_stream_lock_irq() in snd_pcm_status64() * (lock B) wait for tasklet to finish by calling tasklet_unlock_spin_wait() in tasklet_disable_in_atomic() in ohci_flush_iso_completions() of ohci.c thread 1: * (lock B) enter tasklet * (lock A) attempt to acquire substream lock, waiting for it to be released: snd_pcm_stream_lock_irqsave() in snd_pcm_period_elapsed() in update_pcm_pointers() in process_ctx_payloads() in process_rx_packets() of amdtp-stream.c ? tasklet_unlock_spin_wait ohci_flush_iso_completions firewire_ohci amdtp_domain_stream_pcm_pointer snd_firewire_lib snd_pcm_update_hw_ptr0 snd_pcm snd_pcm_status64 snd_pcm ? native_queued_spin_lock_slowpath _raw_spin_lock_irqsave snd_pcm_period_elapsed snd_pcm process_rx_packets snd_firewire_lib irq_target_callback snd_firewire_lib handle_it_packet firewire_ohci context_tasklet firewire_ohci Restore the process context work queue to prevent deadlock AB/BA deadlock competition for ALSA substream lock of snd_pcm_stream_lock_irq() in snd_pcm_status64() and snd_pcm_stream_lock_irqsave() in snd_pcm_period_elapsed(). commit 7ba5ca32fe6e ("ALSA: firewire-lib: operate for period elapse event in process context") Cc: stable@vger.kernel.org Fixes: 7ba5ca32fe6e ("ALSA: firewire-lib: operate for period elapse event i= n process context") Link: https://lore.kernel.org/r/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hze= o4simnl@jn3eo7pe642q/ Reported-by: edmund.raile Closes: https://lore.kernel.org/r/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76h= zeo4simnl@jn3eo7pe642q/ Signed-off-by: Edmund Raile --- sound/firewire/amdtp-stream.c | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index 31201d506a21..a07b0452267d 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -615,16 +615,8 @@ static void update_pcm_pointers(struct amdtp_stream *s, // The program in user process should periodically check the status of i= ntermediate // buffer associated to PCM substream to process PCM frames in the buffe= r, instead // of receiving notification of period elapsed by poll wait. - if (!pcm->runtime->no_period_wakeup) { - if (in_softirq()) { - // In software IRQ context for 1394 OHCI. - snd_pcm_period_elapsed(pcm); - } else { - // In process context of ALSA PCM application under acquired lock of - // PCM substream. - snd_pcm_period_elapsed_under_stream_lock(pcm); - } - } + if (!pcm->runtime->no_period_wakeup) + queue_work(system_highpri_wq, &s->period_work); } } =20 @@ -1864,11 +1856,22 @@ unsigned long amdtp_domain_stream_pcm_pointer(struc= t amdtp_domain *d, { struct amdtp_stream *irq_target =3D d->irq_target; =20 - // Process isochronous packets queued till recent isochronous cycle to ha= ndle PCM frames. if (irq_target && amdtp_stream_running(irq_target)) { - // In software IRQ context, the call causes dead-lock to disable the tas= klet - // synchronously. - if (!in_softirq()) + // This function is called in software IRQ context of + // period_work or process context. + // + // When the software IRQ context was scheduled by software IRQ + // context of IT contexts, queued packets were already handled. + // Therefore, no need to flush the queue in buffer furthermore. + // + // When the process context reach here, some packets will be + // already queued in the buffer. These packets should be handled + // immediately to keep better granularity of PCM pointer. + // + // Later, the process context will sometimes schedules software + // IRQ context of the period_work. Then, no need to flush the + // queue by the same reason as described in the above + if (current_work() !=3D &s->period_work) fw_iso_context_flush_completions(irq_target->context); } =20 --=20 2.45.2 From nobody Thu Dec 18 20:35:34 2025 Received: from mail-43167.protonmail.ch (mail-43167.protonmail.ch [185.70.43.167]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9FA0D18E758 for ; Mon, 29 Jul 2024 21:42:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.70.43.167 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722289353; cv=none; b=nrVPF7zyrb2dQV1Ix5Xg9jIjy+6bYtBaxvDZaCCtgSBW4NRmIRu6CwpNK+tZg7oN0xNEaDoz3S6J+26/jQJnajQoVw3gCZQwKGCbfIqvtMvNTDpS5uviQRHJrMyNgzpduYsZsNJrnoJCYAgOAqeGwRmBJOHegyPvGny+KPZuzRI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722289353; c=relaxed/simple; bh=yRwttLVnCbGv+EaWNEn53RVQvpUMZ1hdRbs/Bciab/U=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=u+P43aq44nJXNX4N9n1sdqbukuZ2PGYZuyU8IzAHgDVxGklWwtRIidYy54eEhxm+vvR8syK+K+3sH2DF1gTqTjuxkMV57Ecc2jCpkiF+jXWc1Kr0WtjGo57BM+pKi/Rq/VD0or3j+LGMpitZ/3+dwjC433fORaVo9Ori9zetWpE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=protonmail.com; spf=pass smtp.mailfrom=protonmail.com; dkim=pass (2048-bit key) header.d=protonmail.com header.i=@protonmail.com header.b=r1l45ICv; arc=none smtp.client-ip=185.70.43.167 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=protonmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=protonmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=protonmail.com header.i=@protonmail.com header.b="r1l45ICv" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1722289349; x=1722548549; bh=yRwttLVnCbGv+EaWNEn53RVQvpUMZ1hdRbs/Bciab/U=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=r1l45ICvIsF9l4qaWTKsGDN7U//lQ6Wzlfv7AI5q3jqSTj4zPz0vLfQZN8DdrnRZ2 FJ732EVN2J5pK19ytKvjmHDhKAnjIexFvG76U6acvLPVVAIWLz5pAS8ud6wC2BdDRw C8AYnNOyrmqUEG9IJwmR9WiKjRwGNBqUsHJaQXMJylxItlKKg0cUQptYATGEBp0D+H IPRqiw4BPz8OXcQJpQwbhBjuA8tIpzcLOGZR3spWZZzaUXCN/BKkYNGo8wRIMdIf+3 FGdUCL8gBGjSyCU6USjUBxRMhrUoHNu5RYEAuBUi3QjSJEBE57BDYYX4aZodQarO8c 6sVxOja8RCQqA== Date: Mon, 29 Jul 2024 21:42:26 +0000 To: o-takashi@sakamocchi.jp, clemens@ladisch.de From: Edmund Raile Cc: tiwai@suse.com, alsa-devel@alsa-project.org, linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v3 3/3] ALSA: firewire-lib: amdtp-stream work queue inline description Message-ID: <20240729214149.752663-4-edmund.raile@protonmail.com> In-Reply-To: <20240729214149.752663-1-edmund.raile@protonmail.com> References: <20240729214149.752663-1-edmund.raile@protonmail.com> Feedback-ID: 43016623:user:proton X-Pm-Message-ID: c866ae9e4304cd5c42ed2f9839a224dbc09265d4 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Replace prior inline description to prevent future deadlock. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hze= o4simnl@jn3eo7pe642q/ Signed-off-by: Edmund Raile --- sound/firewire/amdtp-stream.c | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-) diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index a07b0452267d..7438999e0510 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -1857,20 +1857,12 @@ unsigned long amdtp_domain_stream_pcm_pointer(struc= t amdtp_domain *d, struct amdtp_stream *irq_target =3D d->irq_target; =20 if (irq_target && amdtp_stream_running(irq_target)) { - // This function is called in software IRQ context of - // period_work or process context. - // - // When the software IRQ context was scheduled by software IRQ - // context of IT contexts, queued packets were already handled. - // Therefore, no need to flush the queue in buffer furthermore. - // - // When the process context reach here, some packets will be - // already queued in the buffer. These packets should be handled - // immediately to keep better granularity of PCM pointer. - // - // Later, the process context will sometimes schedules software - // IRQ context of the period_work. Then, no need to flush the - // queue by the same reason as described in the above + // use wq to prevent AB/BA deadlock competition for + // substream lock: + // fw_iso_context_flush_completions() acquires + // lock by ohci_flush_iso_completions(), + // amdtp-stream process_rx_packets() attempts to + // acquire same lock by snd_pcm_elapsed() if (current_work() !=3D &s->period_work) fw_iso_context_flush_completions(irq_target->context); } --=20 2.45.2