From patchwork Sun Jul 28 12:26:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Edmund Raile X-Patchwork-Id: 13743920 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 6988647F4D for ; Sun, 28 Jul 2024 12:26:48 +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=1722169609; cv=none; b=BuHWgopJYWAEyvM5bN0PROFJURXJhcD5CzTwNN1OyQz2cQ7Az+Ra3EQYtYcMnMqjQ4l++ZWuXPOJ69jXAAZsR21GvT2g+YfLBQjytfJQJYPPNqj8TKrsJwgMIB9jLe/168nn5Mxf9UQMcGdUkVjn+2Y78lyD74ZFR0tx1ZGL77U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722169609; 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=Shbv8huEnuKplsjK5MEqt8D7eowmkh4112qb9tERiLGMyfFoeRHtcDrxE9+C8riMIkOzs217p1Ph0vLbkaecjz8SMSfPQ6FQbwJFJsPS/Q8Be+x9cOQZKEVGheq8N8hZyNbbDuefdxxfuXdd0jXl1Tq0C+WaE78L5El7YWppq34= 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=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="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-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 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); }