From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794063527; b=Y6aYuu2aSBznH4rXMDYNovLSxkjiB1KQx+KL0TpsnKhn8K0IugWmYpRouNsvRY9pOuT2 7PDbl3G2BY9cxP1gmZ3BBVvFsmcNVbSRzjhbJU7TTLfZ54+jYPLnpea4nqPotwkQ6HFSQ eIeDyGITabqUx/Jhnf57PpWGu6kaJYGqdoEFn1dJKjLv//1AYwKMPFp7Su9I7woSjLj9A dw08XPPH4EPDUrlutMNadYFhlFlu6kRs5vPYl0zTB7LVOjwfc/yoW6sMg8HZBW0DNg2ds nPy82Wjrkj0PDPkQhK0ezdWO+8H8EInW6khbXvz7+ho4sd0QZwVw7NVCO0slZGEOttA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063527; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=0JsY6phBalt3SWYTLJ2ELuZhXsP2NMwsQgQx7yk6r+g=; b=Wwify3mk+5zNzp1eVBcc09mpT6IyDvE/unoIN04eoQH+Vfl+9/GMXXVVU2D4WEXRFf+Z G7WyZOhoIrV5127S7Yq8UZ5eKhPsrlCif14joo07dvmG+oBfKC/daL/WwPdG86ijpm4NB ilyPwwQG8eah/OfUn/6ToAc931DvZnS84cdIqCOZYA67l8ZHP1Hov7dHsJz101jP5VjMQ 1axFIFOGUy32/uacW5K7ZaM49jCfuUk1fTUEv/+AnNmbIn1DL4XmutlVV9Aj4B4y+PYCo BTZkgSv/PDvCx6mbqzkfN3HswU7jxUgdkrVy0jYBg0nk0S9Q6/VLDvygTy73u7JE7RQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="0G5zbjP/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D87D2606B8BD; Sat, 7 Nov 2026 14:58:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=0G5zbjP/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79B851F0089F; Sat, 7 Nov 2026 14:58:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063526; bh=0JsY6phBalt3SWYTLJ2ELuZhXsP2NMwsQgQx7yk6r+g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=0G5zbjP/T9is+Y6b8604wO/YEJl4MBAStnROoAzq2hikMg/xXoppCCwOfo3RupGea I/2atq45ntX37MYR4+KbCyoSNLTP6yq8qv2DMxhwjrb8KYXPuCA8/EibnieF72htiC osFQLkoqcOLSkn7FM9ARyU3hG+Wox29ZmFNxpQzw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sashiko , Takashi Iwai , Sasha Levin Subject: [PATCH 6.18 666/869] ALSA: line6: Handle period elapsed calls outside the locks Date: Sat, 7 Nov 2026 08:55:48 -0500 Message-ID: <20261107134915.718481178@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai [ Upstream commit 443ed4edc2678cc51c5a01e7dffc4c890be40051 ] LINE6 driver may call snd_pcm_period_elapsed() for both playback and capture substreams at processing the playback substream, and this may lead to a ABBA deadlock. Move the actual calls of snd_pcm_period_elapsed() outside the locks for avoiding it. The capture period notification at submitting the initial playback URBs (only with the impulse mode) is simply skipped, as it's done in the lock context; it'll be caught up at the next period. Fixes: f56742cc4189 ("ALSA: line6: Add LINE6_CAP_IN_NEEDS_OUT, a void playback stream during capture") Reported-by: Sashiko Closes: https://sashiko.dev/#/bug/linux-5a9de389-e6ea-410d-8322-e74e14152603 Cc: Link: https://patch.msgid.link/20261020113118.234689-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/usb/line6/capture.c | 25 ++++++++++++++++--------- sound/usb/line6/capture.h | 2 +- sound/usb/line6/playback.c | 31 +++++++++++++++++++++---------- 3 files changed, 38 insertions(+), 20 deletions(-) diff --git a/sound/usb/line6/capture.c b/sound/usb/line6/capture.c index 9ef4faa006a03..46acd2f44c440 100644 --- a/sound/usb/line6/capture.c +++ b/sound/usb/line6/capture.c @@ -125,24 +125,21 @@ void line6_capture_copy(struct snd_line6_pcm *line6pcm, char *fbuf, int fsize) line6pcm->in.pos_done -= runtime->buffer_size; } -void line6_capture_check_period(struct snd_line6_pcm *line6pcm, int length) +/* update the capture position and check whether we need period_elapsed call */ +bool line6_capture_check_period(struct snd_line6_pcm *line6pcm, int length) { - struct snd_pcm_substream *substream = - get_substream(line6pcm, SNDRV_PCM_STREAM_CAPTURE); - line6pcm->in.bytes += length; if (line6pcm->in.bytes >= line6pcm->in.period) { line6pcm->in.bytes %= line6pcm->in.period; - spin_unlock(&line6pcm->in.lock); - snd_pcm_period_elapsed(substream); - spin_lock(&line6pcm->in.lock); + return true; } + return false; } /* * Callback for completed capture URB. */ -static void audio_in_callback(struct urb *urb) +static bool handle_audio_in(struct urb *urb) { int i, index, length = 0, shutdown = 0; struct snd_line6_pcm *line6pcm = (struct snd_line6_pcm *)urb->context; @@ -207,8 +204,18 @@ static void audio_in_callback(struct urb *urb) if (!test_bit(LINE6_STREAM_IMPULSE, &line6pcm->in.running) && test_bit(LINE6_STREAM_PCM, &line6pcm->in.running)) - line6_capture_check_period(line6pcm, length); + return line6_capture_check_period(line6pcm, length); } + + return false; +} + +static void audio_in_callback(struct urb *urb) +{ + struct snd_line6_pcm *line6pcm = (struct snd_line6_pcm *)urb->context; + + if (handle_audio_in(urb)) + snd_pcm_period_elapsed(get_substream(line6pcm, SNDRV_PCM_STREAM_CAPTURE)); } /* open capture callback */ diff --git a/sound/usb/line6/capture.h b/sound/usb/line6/capture.h index 90572dae134ee..628315389efcf 100644 --- a/sound/usb/line6/capture.h +++ b/sound/usb/line6/capture.h @@ -17,7 +17,7 @@ extern const struct snd_pcm_ops snd_line6_capture_ops; extern void line6_capture_copy(struct snd_line6_pcm *line6pcm, char *fbuf, int fsize); -extern void line6_capture_check_period(struct snd_line6_pcm *line6pcm, +extern bool line6_capture_check_period(struct snd_line6_pcm *line6pcm, int length); extern int line6_create_audio_in_urbs(struct snd_line6_pcm *line6pcm); extern int line6_submit_audio_in_all_urbs(struct snd_line6_pcm *line6pcm); diff --git a/sound/usb/line6/playback.c b/sound/usb/line6/playback.c index 2e70ca5456c5a..495a983a0c51f 100644 --- a/sound/usb/line6/playback.c +++ b/sound/usb/line6/playback.c @@ -136,6 +136,8 @@ static void add_monitor_signal(struct urb *urb_out, unsigned char *signal, /* Find a free URB, prepare audio data, and submit URB. must be called in line6pcm->out.lock context + Returns 1 if snd_pcm_period_elapsed() needs to be called for the + capture stream after releasing the lock, 0 if not, or a negative error */ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) { @@ -151,6 +153,7 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) line6pcm->properties->rates.rats[0].den * (line6pcm->line6->intervals_per_second / LINE6_ISO_INTERVAL); struct urb *urb_out; + bool capture_period_elapsed = false; index = find_first_zero_bit(&line6pcm->out.active_urbs, line6pcm->line6->iso_buffers); @@ -260,8 +263,9 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) urb_out->transfer_buffer, urb_out-> transfer_buffer_length); - line6_capture_check_period(line6pcm, - urb_out->transfer_buffer_length); + capture_period_elapsed = + line6_capture_check_period(line6pcm, + urb_out->transfer_buffer_length); } } else { if (!(line6pcm->line6->properties->capabilities & LINE6_CAP_HWMON) @@ -283,24 +287,26 @@ static int submit_audio_out_urb(struct snd_line6_pcm *line6pcm) dev_err(line6pcm->line6->ifcdev, "URB out #%d submission failed (%d)\n", index, ret); - return 0; + return capture_period_elapsed; } /* Submit all currently available playback URBs. must be called in line6pcm->out.lock context + The capture period notification is skipped here since we can't call + snd_pcm_period_elapsed() in the lock; it'll be caught up at the next one. */ int line6_submit_audio_out_all_urbs(struct snd_line6_pcm *line6pcm) { - int ret = 0, i; + int ret, i; for (i = 0; i < line6pcm->line6->iso_buffers; ++i) { ret = submit_audio_out_urb(line6pcm); if (ret < 0) - break; + return ret; } - return ret; + return 0; } /* @@ -316,6 +322,8 @@ static void audio_out_callback(struct urb *urb) const int bytes_per_frame = line6pcm->properties->bytes_per_channel * line6pcm->properties->playback_hw.channels_max; + bool capture_period_elapsed = false; + bool playback_period_elapsed = false; #if USE_CLEAR_BUFFER_WORKAROUND memset(urb->transfer_buffer, 0, urb->transfer_buffer_length); @@ -358,19 +366,22 @@ static void audio_out_callback(struct urb *urb) shutdown = 1; if (!shutdown) { - submit_audio_out_urb(line6pcm); + capture_period_elapsed = submit_audio_out_urb(line6pcm) > 0; if (test_bit(LINE6_STREAM_PCM, &line6pcm->out.running)) { line6pcm->out.bytes += length; if (line6pcm->out.bytes >= line6pcm->out.period) { line6pcm->out.bytes %= line6pcm->out.period; - spin_unlock(&line6pcm->out.lock); - snd_pcm_period_elapsed(substream); - spin_lock(&line6pcm->out.lock); + playback_period_elapsed = true; } } } spin_unlock_irqrestore(&line6pcm->out.lock, flags); + + if (capture_period_elapsed) + snd_pcm_period_elapsed(get_substream(line6pcm, SNDRV_PCM_STREAM_CAPTURE)); + if (playback_period_elapsed) + snd_pcm_period_elapsed(substream); } /* open playback callback */ -- 2.53.0