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: 13745832 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 A465B18E76D for ; Mon, 29 Jul 2024 21:42:25 +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=1722289347; cv=none; b=bKHSJScKpRD/pUhNxgeUdYY5fVCjy4qhtsZkwc9kDCQgJXZcu5hMFC3EXUCMarI9TfY3VxiEGpfQUHihgeAkSMSfCs9a6F+QV5yjMcGP7qdmJW379vSKuHvr5E9nZAuyFZms8rFEu312KE/02mWx4mTDnqyjjJdgbVluRiEyGeI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722289347; c=relaxed/simple; bh=8iM24PCjxernsCmrbqINdswXHOWozrexHbwMNneqCnQ=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ajw/TJtHjQzwsZWlA36QGxYBdZDoWuPZmlpuRW28WFOj2Vw2KVE5lJr88QyLkl5qjYH9L/k4xaG1rwwefxZiHPFgOtwEvLyV9DFb40V+D2SwNOUzIrDHUOquhUV5Hz2udIdnWSp1tZ5Badn+xLDg/a3KNmVehFm0wUwu1YUUXH8= 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=rdiI80yt; 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="rdiI80yt" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1722289343; x=1722548543; bh=ozHc3JMbelPHTptoBAz/6oNgi6Ns5+gebFLiu+Sf76c=; 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=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 Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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); }