From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 AA3CB79945; Wed, 7 Aug 2024 15:15:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723043721; cv=none; b=N0GRd00+uvVaCwnYGoRia4qniwqve8ts0xJz6S7tUqBG1xB44d/7UCSSo/qMjUYqgF5XuGBrZvJMGxSia/OAog9zU488OYIV0OafAMM6hMETO4+0ZemwbYlRgmTOTdM5xDRaHtDe1avP72L9YBx5ybOZkqvQ20EzojVHFMl4Kzg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723043721; c=relaxed/simple; bh=P5EM4ayrenF0CTzL0oxICcjikwuUBY2dObYWVuwHmg8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CeP+Hx4KfrDzxlL6vwV2u0WMIDi6SiC8up1Lp/8E15xXBQEZ8ZGusajyQlVcUU6jtMgnRTy2KAstkaUWnGkk7p6eozc3cfHjShR7QSrlKfHopaJQrRWVzYn1WiW7gOFxo5DxNWxpb6a7T/OoJLZBOqT18+7R7qtLaYnD1LmRNqU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1+jYIzM8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1+jYIzM8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A919C32781; Wed, 7 Aug 2024 15:15:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723043721; bh=P5EM4ayrenF0CTzL0oxICcjikwuUBY2dObYWVuwHmg8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1+jYIzM821HeN38llBTV0+AX5TLvPCGPiBrbeiGdMJuVDk4yO9k3q0Ui1f1oV/9A+ /BrGZKr+1BNPWBkWrUgmJIpooCwmofWtKafeJbTWH/kIOWvqiEqJYEeHWyalUOGeZb uwkdjIIYGJ1tbJct8AlV8idZ4kww7Z5tyg0TCfMQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "edmund.raile" , Edmund Raile , Takashi Sakamoto , Takashi Iwai Subject: [PATCH 6.1 75/86] Revert "ALSA: firewire-lib: operate for period elapse event in process context" Date: Wed, 7 Aug 2024 17:00:54 +0200 Message-ID: <20240807150041.760924613@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240807150039.247123516@linuxfoundation.org> References: <20240807150039.247123516@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Edmund Raile commit 3dab73ab925a51ab05543b491bf17463a48ca323 upstream. 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 Reviewed-by: Takashi Sakamoto Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20240730195318.869840-3-edmund.raile@protonmail.com Signed-off-by: Greg Kroah-Hartman --- sound/firewire/amdtp-stream.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -613,16 +613,8 @@ static void update_pcm_pointers(struct a // 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); } } @@ -1752,11 +1744,14 @@ unsigned long amdtp_domain_stream_pcm_po { 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); }