From nobody Mon Feb 9 01:06:37 2026 Received: from mail-40138.protonmail.ch (mail-40138.protonmail.ch [185.70.40.138]) (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 16B7129A1; Sun, 28 Jul 2024 12:26:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.70.40.138 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722169606; cv=none; b=N9J2fEM7wru/HHXiL1g1Lu3mvdbTLzTEcRKkEmc9pS45tLZKjg+xoNdPlMdMvSbIhqM5pVNMP21gO1tkKG7JjF9kcvH9WKNo4tvEq2lcfvmbObRZfr0/WHwghqb47axgF89s7Eh1T/08qk6Ap6io7y2WnDeNkgTB75s0oTTQuVg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722169606; c=relaxed/simple; bh=DJ0+aZtEj0tlvzzOMHpKTswqeirhVvMiNDMLCWc88r4=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=XRXqBerf4WLJNNZZKnY0cZyIWL9on2f+cTy5uux2KwagmteXX6ryBoXTdOpS9Hl5pEGuBqFO47+W2pF7GmSb/mm9S9ewBnZX9jbj2RUpQ5mRoWLmrkldqudO6dhH8sSAGFw4Qjd9ibZ1sFfzvYgET9i2A6nkYMI019CYogVXLik= 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=uj2CUCDb; arc=none smtp.client-ip=185.70.40.138 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="uj2CUCDb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1722169596; x=1722428796; bh=Q6ujAQ2rqdbruPutUk79q/5IjtuZzJ+fzsg6fKKzv+8=; 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=uj2CUCDbsIVhAZ4sYNFgcQwtDm9dJ1tXuYpZa4Dc2CQD34BZnZwIpdi48E/ScjxP6 LN6mvkAn2ohg2OyQXZWpOwq2YT+wd+zNqz7XztNB6XXDKGUJCZ1qEIgzB5g4S2f9ym 05BOT5HShd/VVHxTe24xaQFvMALyKafSn+jPJOsnUr8/LQ5wgnQYTo9AC/+SWULclc M8wsnG85VjtKr1rxMsy/QL6o/HpMSYoFnnm+qWrJ9wRjXDvqx99Mkw8bi3NM8rVdla 42EuxXEocPT7ZCxiioGplSm9xM+p/P5RoGB737h/wLYcBM4aKNwyin1Y+4RhWaoG4G NUfz23ddqG+Tg== Date: Sun, 28 Jul 2024 12:26:31 +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, edmund.raile@protonmail.com, stable@vger.kernel.org Subject: [PATCH v2 1/2] ALSA: firewire-lib: restore workqueue for process context Message-ID: <20240728122614.329544-2-edmund.raile@protonmail.com> In-Reply-To: <20240728122614.329544-1-edmund.raile@protonmail.com> References: <20240728122614.329544-1-edmund.raile@protonmail.com> Feedback-ID: 43016623:user:proton X-Pm-Message-ID: 066da7d5dd20465512e2d7eb025b7d16267a2578 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 deadlock between process context and softIRQ context: 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/ Reported-by: edmund.raile 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 Mon Feb 9 01:06:37 2026 Received: from mail-0301.mail-europe.com (mail-0301.mail-europe.com [188.165.51.139]) (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 5A9343F8C7 for ; Sun, 28 Jul 2024 12:27:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=188.165.51.139 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722169624; cv=none; b=fagsoYJg8Fje+fJy1Bmk5zZUzQabCf7npvmqbXh8h9SECrMXHfFhfT9pAsZOXol1Hl/sJDiF6INdbGaDdprSZVjwHXaF3JsP+l5Abr9ZEQScTc/QNOFA0Y5ODDuRBuimxBsn/E8AIVN3hgYMbiChd7N68uPBF0ybJF7KzqHIQaI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722169624; c=relaxed/simple; bh=zYeI0RXOOsfL8/wFCi+vO2omAPFQKXW51I6FzL+Chhs=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GSegY8L6EOBe+AvKg2YwtCoE9ALgWKMEBHlDaxJL+Gpi7qIfQ/KTksg51h3tD2W1MKGXTBV/boZ48vfz3rHmP4ST2CEM0nNi//x+Pop+7U9sC2WLs8zKPBtzKZTsMynaMoUgQFpHX7/igBb/15fWV/eIDu13zNLJKagBJaPL4ds= 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=PNzFgFyW; arc=none smtp.client-ip=188.165.51.139 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="PNzFgFyW" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1722169606; x=1722428806; bh=KBafj0W+hLUSbIhjE/xmSCOMhfBOVKrA7riUOgwT7ls=; 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=PNzFgFyWb4p0LeN6x70PPWCBUc4WMARzJSh2GaQJphAhFKVNxAqFMS0HLNUXMMA50 6OcF86EhUGMNytJxoA7YUu1nEj0aJ0W9cTwGI4OXpOUy9jQIuWSogDD2ryNLiykApv CJkMsLkt6bQWfj68IEIZvWtWoLO6exjhw+gH9D1iPWDEt7+dlc7jAwhBwM7Em+R7/U EN1ea9PcF5ms7lIg6VyERaM4G9qCtc5jnUW7HKBHfwnb9X8XySsAeZFCVAqg2oZ4qP +u44D1rBNlaNs0OBiNuaM+vtzl5OK4B2zwyu4O6Yv+lYP2WwM3fdyxLwFAtFpt0PIa uAKcfJP1KesoA== Date: Sun, 28 Jul 2024 12:26:39 +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, edmund.raile@protonmail.com, stable@vger.kernel.org Subject: [PATCH v2 2/2] ALSA: firewire-lib: prevent deadlock between process and softIRQ context Message-ID: <20240728122614.329544-3-edmund.raile@protonmail.com> In-Reply-To: <20240728122614.329544-1-edmund.raile@protonmail.com> References: <20240728122614.329544-1-edmund.raile@protonmail.com> Feedback-ID: 43016623:user:proton X-Pm-Message-ID: de55fd5e8a28ebd761c5c600cc8525dc8a590299 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" 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 a deadlock with eventual system freeze under ALSA operation: A. In the process context * (lock A) Acquiring spin_lock by snd_pcm_stream_lock_irq() in snd_pcm_status64() * (lock B) Then attempt to enter tasklet B. In the softIRQ context * (lock B) Enter tasklet * (lock A) Attempt to acquire spin_lock by snd_pcm_stream_lock_irqsave() in snd_pcm_period_elapsed() ? 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 between ALSA substream process context spin_lock of snd_pcm_stream_lock_irq() in snd_pcm_status64() and OHCI 1394 IT softIRQ context spin_lock of snd_pcm_stream_lock_irqsave() in snd_pcm_period_elapsed(). 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 Signed-off-by: Edmund Raile --- sound/firewire/amdtp-stream.c | 21 ++++++++------------- 1 file changed, 8 insertions(+), 13 deletions(-) diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index 31201d506a21..c037d7de1fdc 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -615,16 +615,9 @@ 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) + // wq used with amdtp_domain_stream_pcm_pointer() to prevent deadlock + queue_work(system_highpri_wq, &s->period_work); } } =20 @@ -1866,9 +1859,11 @@ unsigned long amdtp_domain_stream_pcm_pointer(struct= amdtp_domain *d, =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()) + // use wq to prevent deadlock between process context spin_lock + // of snd_pcm_stream_lock_irq() in snd_pcm_status64() and + // softIRQ context spin_lock of snd_pcm_stream_lock_irqsave() + // in snd_pcm_period_elapsed() + if ((!in_softirq()) && (current_work() !=3D &s->period_work)) fw_iso_context_flush_completions(irq_target->context); } =20 --=20 2.45.2