From patchwork Sun Jul 28 12:26:21 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Edmund Raile X-Patchwork-Id: 13743918 Received: from mail-40140.protonmail.ch (mail-40140.protonmail.ch [185.70.40.140]) (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 5126829A1; Sun, 28 Jul 2024 12:26:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.70.40.140 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722169597; cv=none; b=boPzfnm6REETLhKa3Asx/P47/iR6CLvTnbl4OPlQXr3SSr1H9R1XenBPoPCsGHwW4kM28Sby6osBNWHzp2UJxi0LYalR6oo8IP/GVFTPZQSdHbTRZ+LAPyUrJhHg5HegdhiUFXP2ujbdwaIlg2yfutZwbfYvOOhxUrIRaJnK0Wg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722169597; c=relaxed/simple; bh=MAxeEGmgS9693J0PQhUIRbfqko2MsleF4u/sBRGsb4Y=; h=Date:To:From:Cc:Subject:Message-ID:MIME-Version:Content-Type; b=CiI5SQT825/AkgJViCIzGeXZKVF7jYUzBj4CJKq8PH5g7of0PGrN3tizq822RTSh1+2gyyZYDCNtmObyja0Rvh96ZV+WO95BpquzmfMLS+1NK5gQl7ucj5bhSYMIfsaclzI0x5FQXqJ41teS6A4d9dzUiLb1onSmyxsC5HzF8W8= 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=svThna/8; arc=none smtp.client-ip=185.70.40.140 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="svThna/8" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1722169588; x=1722428788; bh=74jrJoeOKYDJalJmIabOoA19hszvpDADNvzc31C/j48=; h=Date:To:From:Cc:Subject:Message-ID:Feedback-ID:From:To:Cc:Date: Subject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector; b=svThna/84zGaTHZ4yVuXTMAPuIKprGMAJgK7BKsrz/2IJ3mtALCljNiP7PKoeeloi 9UZK7bQDnEYP7Dxy6bvH59KKLXVBUJkRVGmyGb+at+aSem6UZgzWEHL6xDkBKhbDLB Fw/RczRop40p2PrH0pe1myvGS8NUKQ9J4b523FNjndbt6c4n318/c4Hpy+Ph5sWmmq 5ffzHo++EXN+j7+C1xr07rOYxCWzkxOilSJ9guvUci4RdebBwq6G2LmqP69+1DRSu3 bR37HpKHPxJ+cuuM3DDa8i82S0Emn4il8DmdF67z2h38/7ZqwoSIZBdhKvTO71HqrQ D0Y68FqqhpLrQ== Date: Sun, 28 Jul 2024 12:26:21 +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 0/2] ALSA: firewire-lib: restore process context workqueue to prevent deadlock Message-ID: <20240728122614.329544-1-edmund.raile@protonmail.com> Feedback-ID: 43016623:user:proton X-Pm-Message-ID: 7405776f7170639ffa300581e17a2b4f23d866bf Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This patchset serves to prevent a deadlock between process context and softIRQ context: 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 The issue has been reported as a regression of kernel 5.14: Link: https://lore.kernel.org/regressions/kwryofzdmjvzkuw6j3clftsxmoolynljztxqwg76hzeo4simnl@jn3eo7pe642q/T/#u ("[REGRESSION] ALSA: firewire-lib: snd_pcm_period_elapsed deadlock with Fireface 800") 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. Commit b5b519965c4c ("ALSA: firewire-lib: obsolete workqueue for period update") belongs to the same patch series and removed the now-unused workqueue entirely. Though being observed on RME Fireface 800, this issue would affect all Firewire audio interfaces using ohci amdtp + pcm streaming. ALSA streaming, especially under intensive CPU load will reveal this issue the soonest due to issuing more hardIRQs, with time to occurrence ranging from 2 secons to 30 minutes after starting playback. to reproduce the issue: direct ALSA playback to the device: mpv --audio-device=alsa/sysdefault:CARD=Fireface800 Spor-Ignition.flac Time to occurrence: 2s to 30m Likelihood increased by: - high CPU load stress --cpu $(nproc) - switching between applications via workspaces tested with i915 in Xfce PulsaAudio / PipeWire conceal the issue as they run PCM substream without period wakeup mode, issuing less hardIRQs. Backport note: Also applies to and fixes on (tested): 6.10.2, 6.9.12, 6.6.43, 6.1.102, 5.15.164 Edmund Raile (2): ALSA: firewire-lib: restore workqueue for process context ALSA: firewire-lib: prevent deadlock between process and softIRQ context sound/firewire/amdtp-stream.c | 36 ++++++++++++++++++++++------------- sound/firewire/amdtp-stream.h | 1 + 2 files changed, 24 insertions(+), 13 deletions(-)