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Sun, 28 Jul 2024 14:31:00 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 548C5F8007E Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key, unprotected) header.d=protonmail.com header.i=@protonmail.com header.a=rsa-sha256 header.s=protonmail3 header.b=m42Dw/u7 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1722169860; x=1722429060; 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=m42Dw/u7Urz+pXrO7pgznBTTpCFn5Twt/QUlrUJSpHkuI44zUA+VoGiTyBGPpdVKF Q4ZXYe5Prj3XWgQB3gLQLycN0c83wDoIxe7PUQLp19J2NhINBgO0FhGez6pO6x6e5T GGQvcpljULF/A8z4SL0WVV77fsUB4TFICqIeV9tAJenNnFKSeP3kVCC2eYq/Q9h7eo eBGkjsPvfl8gY+vkbZw3/FMhGThmzlOIsWfsMYG0dkVeyWLxUbTYK3JILW4yf+gd9K d1BkCUX7gaRida4Ndff1UoqVxKaGDDhI4PebbRzegdExTvioEdLYtttbS5hhAKOhDe XfLMH6us46Xhw== Date: Sun, 28 Jul 2024 12:30:55 +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 process context workqueue to prevent deadlock Message-ID: <20240728123041.330216-2-edmund.raile@protonmail.com> In-Reply-To: <20240728123041.330216-1-edmund.raile@protonmail.com> References: <20240728123041.330216-1-edmund.raile@protonmail.com> Feedback-ID: 43016623:user:proton X-Pm-Message-ID: cac6802b9d6e3d2461bf4a2b8402fc3fc133ff58 MIME-Version: 1.0 X-MailFrom: edmund.raile@protonmail.com X-Mailman-Rule-Hits: nonmember-moderation 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 Message-ID-Hash: DEA3Y4AHR6BIIUJ3X2SPBNFYQDMKOCBY X-Message-ID-Hash: DEA3Y4AHR6BIIUJ3X2SPBNFYQDMKOCBY X-Mailman-Approved-At: Wed, 31 Jul 2024 08:49:10 +0000 X-Mailman-Version: 3.3.9 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: 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/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hzeo4simnl@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 +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 = flags; s->context = ERR_PTR(-1); mutex_init(&s->mutex); + INIT_WORK(&s->period_work, pcm_period_work); s->packet_index = 0; 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 = 0; s->pcm_period_pointer = 0; } @@ -624,6 +628,16 @@ static void update_pcm_pointers(struct amdtp_stream *s, } } +static void pcm_period_work(struct work_struct *work) +{ + struct amdtp_stream *s = container_of(work, struct amdtp_stream, + period_work); + struct snd_pcm_substream *pcm = READ_ONCE(s->pcm); + + if (pcm) + snd_pcm_period_elapsed(pcm); +} + static int queue_packet(struct amdtp_stream *s, struct fw_iso_packet *params, bool sched_irq) { @@ -1910,6 +1924,7 @@ static void amdtp_stream_stop(struct amdtp_stream *s) return; } + cancel_work_sync(&s->period_work); fw_iso_context_stop(s->context); fw_iso_context_destroy(s->context); s->context = 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 { /* 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; From patchwork Sun Jul 28 12:31:03 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Edmund Raile X-Patchwork-Id: 815684 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 (unknown [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 1DD11C3DA7F for ; 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b=a1KjOzNcElvwgZR+zofIEb5MYjjMzwqyPOZl0LHgc9yPH3JVWDU238enBD++qXpNi OTXQHGgqoPmOJr48llF0f1pJsHbon+M0sF8YUnHjhW5uaGqxlQ3DVcWrUXM4IATro9 n2DLow+7vrkx3HqthV9IemMBBKmVUJQu9TnkzPMcIhgLFVlcCLgy2L4JhAa7Cg1fsk wxl7zp0TTjNYaMwe8Xu7A3Zckg7U1WjzVi34ECZPFW4kpW+fb9ysoV6EzK/OhnZEtb 3FETPM8X8DvuSdrhlDcPurtEUmTdgJ3PInl4VX4nxp/s6GAjSVFuUFs5IZCqDBAT24 KyiZInE5KhP6w== Date: Sun, 28 Jul 2024 12:31:03 +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: restore process context workqueue to prevent deadlock Message-ID: <20240728123041.330216-3-edmund.raile@protonmail.com> In-Reply-To: <20240728123041.330216-1-edmund.raile@protonmail.com> References: <20240728123041.330216-1-edmund.raile@protonmail.com> Feedback-ID: 43016623:user:proton X-Pm-Message-ID: 5e1ed2a306242a75e68ed5c02831d4a3f6f0a481 MIME-Version: 1.0 X-MailFrom: edmund.raile@protonmail.com X-Mailman-Rule-Hits: nonmember-moderation 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 Message-ID-Hash: H4UOEHOLJGJI6PC357O37REOTV4FQOXB X-Message-ID-Hash: H4UOEHOLJGJI6PC357O37REOTV4FQOXB X-Mailman-Approved-At: Wed, 31 Jul 2024 08:49:11 +0000 X-Mailman-Version: 3.3.9 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: 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 in process context") Link: https://lore.kernel.org/r/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hzeo4simnl@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 intermediate // buffer associated to PCM substream to process PCM frames in the buffer, 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); } } @@ -1866,9 +1859,11 @@ unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d, // Process isochronous packets queued till recent isochronous cycle to handle PCM frames. if (irq_target && amdtp_stream_running(irq_target)) { - // In software IRQ context, the call causes dead-lock to disable the tasklet - // 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() != &s->period_work)) fw_iso_context_flush_completions(irq_target->context); }