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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: PNQUTOPQ6BJSHYPNYNVKCZNWXZQK4P4L X-Message-ID-Hash: PNQUTOPQ6BJSHYPNYNVKCZNWXZQK4P4L X-Mailman-Approved-At: Wed, 31 Jul 2024 08:50:12 +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 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/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hzeo4simnl@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 +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 Mon Jul 29 21:42:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Edmund Raile X-Patchwork-Id: 816334 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 BD99DC3DA7F for ; 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b=rdiI80yt1jkTRytui3ySgkcyyiiE9z16O9rdUOu+B2k7sf5p3VjJxNZ0DDTjLZj3E kQD3aygEjkwWrGcOxme1i7U3lXrk+FHrjAiDEmHdgoCdxnNrrl/dDlcK4sZlxVJRvz O4JJgqYfCK0+S/F8kbptDh3RlTaupfS+2qNVCNea4/AP0uP05nxk0F8ZaQytoCTOIa Xmnk6zOIxTOEDt2zVJ6qg/PFra3dxVmljEcsi1zpqoWWndzx6dWFKcoBpyssAhizQ+ Bth8dPfJTrqXxi/TF0EQ3FOuthiZWu3E3gErkwRUiFtguCaG0HArijSdglP2VVOCth c4nAUypyRrusQ== Date: Mon, 29 Jul 2024 21:42:18 +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 2/3] Revert "ALSA: firewire-lib: operate for period elapse event in process context" Message-ID: <20240729214149.752663-3-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: 613ccd6c4c053b9a39492559685e3884775e4347 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: UTR4K67GUY3BBBT2GWFPHIEXQMEFSZPG X-Message-ID-Hash: UTR4K67GUY3BBBT2GWFPHIEXQMEFSZPG X-Mailman-Approved-At: Wed, 31 Jul 2024 08:50:12 +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 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 in process context") Link: https://lore.kernel.org/r/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hzeo4simnl@jn3eo7pe642q/ Reported-by: edmund.raile Closes: https://lore.kernel.org/r/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hzeo4simnl@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 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) + queue_work(system_highpri_wq, &s->period_work); } } @@ -1864,11 +1856,22 @@ unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d, { struct amdtp_stream *irq_target = d->irq_target; - // 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()) + // 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() != &s->period_work) fw_iso_context_flush_completions(irq_target->context); } From patchwork Mon Jul 29 21:42:26 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Edmund Raile X-Patchwork-Id: 815681 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 9EA98C3DA64 for ; Wed, 31 Jul 2024 08:54:47 +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 6BE452D61; Wed, 31 Jul 2024 10:54:31 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 6BE452D61 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1722416081; bh=yRwttLVnCbGv+EaWNEn53RVQvpUMZ1hdRbs/Bciab/U=; h=Date:To:From:Cc:Subject:In-Reply-To:References:List-Id: List-Archive:List-Help:List-Owner:List-Post:List-Subscribe: List-Unsubscribe:From; b=MGGuZEbauscCz4RLQ2op5ybZAmumcBbC56bA+RhVtIeePS+Ox943z3mOay4wCtSOz 0YSDYkX6agO7Y/8SJCssk0LZYFjeQ7H4K0mB2XfHrjZj1rTxCEs+O0o9JaKD6Wz4fL K5NmfVlNsELVe0+JqWd44EJC29uYqEGcoDqKaJBA= Received: by alsa1.perex.cz (Postfix, from userid 50401) id F1A5CF80C8C; Wed, 31 Jul 2024 10:50:18 +0200 (CEST) Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id 6F4EDF80CB8; Wed, 31 Jul 2024 10:50:18 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id CBAD2F80448; Mon, 29 Jul 2024 23:51:41 +0200 (CEST) Received: from mail-0201.mail-europe.com (mail-0201.mail-europe.com [51.77.79.158]) (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 151CDF802DB for ; Mon, 29 Jul 2024 23:44:07 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 151CDF802DB 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=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 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: B2YXJHHWEH753SFIJJ56VDWFZF3CKVKI X-Message-ID-Hash: B2YXJHHWEH753SFIJJ56VDWFZF3CKVKI X-Mailman-Approved-At: Wed, 31 Jul 2024 08:50:12 +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: Replace prior inline description to prevent future deadlock. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hzeo4simnl@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(struct amdtp_domain *d, struct amdtp_stream *irq_target = d->irq_target; 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() != &s->period_work) fw_iso_context_flush_completions(irq_target->context); }