From patchwork Tue Jul 30 19:53:29 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Edmund Raile X-Patchwork-Id: 13747843 Received: from mail-43166.protonmail.ch (mail-43166.protonmail.ch [185.70.43.166]) (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 9BEF918CBE1; Tue, 30 Jul 2024 19:53:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.70.43.166 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722369221; cv=none; b=QMcmthRd2UPKDc5TuzJ6ANyE82zGA5UIh+cBw4tYDAQqNWBYShFwtDY16e0YAA+mJ+SxDCphp8dHcebZN++SXWSQ3W7W5kEjp/vcC590cMZvBaIcV033V+mq3mnvny7JLxej8EDWlQE1ZkG0ogL7fP+cfprnisO7qrmhfpyMEYw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722369221; c=relaxed/simple; bh=7t2pb5/6Q/LkGZmrG+ccU7x8AQ7CkBLsXiBJgc4OsqY=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=nXsE3DuVG/sf7NC38HZtuaYd08JMCQB0RjTg8jIlJUNBaViWyKFi2mO6s+izH23T0KpTx2BX8c8C82iZA4Uq2XG7UmqoNF1FDIYOr+q3N0Fg+iEoe0CeW1d0R3QwZ6UVGZ6NhYpRZ3wIvUadJSxCPDhDh5omk2xbVPVV9u4FrTc= 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=VNOFhtsG; arc=none smtp.client-ip=185.70.43.166 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="VNOFhtsG" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1722369211; x=1722628411; bh=jywWkedUWZsQUoqanntjxmq0rUgTqu6frKuhe/bbf+o=; 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=VNOFhtsGfwXJInt2Au4rVPgZxoMEG5asE978MEg4iNvPRB3rp4pvsEp8+vfEWT5rn nHbSJ0AOwcldCFHQo9UAivw+hkoaw6AqZMUIq2IpSJZazo8A1MIJvOZLPtV8BPTEO9 9NaXQsPk9VdVjb3Uq0rwYqdTrazThIEZqaam6rCidKU73Gj9rPYPwEM/5YhcgkpeDe a6dDyQ5UuZ8m0XgotsZqQL2nvTeegP4QkgTzwLjUxou7Qnt/kcKbbw96FiEHNqKguP YZ1C1VYO50l2Fv0r1tDB8vTOtFQmH+SHkvOStfjgrguq+jjmT2xYe7nX7FEQ8oJHpc TroRmWsf5mqMg== Date: Tue, 30 Jul 2024 19:53:29 +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 v4 2/2] Revert "ALSA: firewire-lib: operate for period elapse event in process context" Message-ID: <20240730195318.869840-3-edmund.raile@protonmail.com> In-Reply-To: <20240730195318.869840-1-edmund.raile@protonmail.com> References: <20240730195318.869840-1-edmund.raile@protonmail.com> Feedback-ID: 43016623:user:proton X-Pm-Message-ID: ae12f90033d54c69dac6f2fe2a36cdef77a7bfee 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(). revert commit 7ba5ca32fe6e ("ALSA: firewire-lib: operate for period elapse event in process context") Replace inline description to prevent future deadlock. Cc: stable@vger.kernel.org Fixes: 7ba5ca32fe6e ("ALSA: firewire-lib: operate for period elapse event in process context") Reported-by: edmund.raile Closes: https://lore.kernel.org/r/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hzeo4simnl@jn3eo7pe642q/ Signed-off-by: Edmund Raile --- sound/firewire/amdtp-stream.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index 31201d506a21..7438999e0510 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 +1856,14 @@ 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()) + // 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); }