From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 864CC46A606; Tue, 21 Jul 2026 15:48:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784648883; cv=none; b=BPsPLDxgdhAU4TiV/HvDJF3jXYT7aO5Q5GELB2Ccj/1NPlhp445i7mGLWv99jH9+UTzXvyIeWeKocjdHjuhkhM5c6XrzhZrMW/HQZW8QRWKjDozmrmWTtSlT9b80aRgE1VhH3PagyM51/Wqnhdp8Y8uyConv96cSj49+kh9q/t0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784648883; c=relaxed/simple; bh=XMBQ5jjowgPnH9c55KfYMbtP7XxFmHCbt17GFi9iWEU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=cDasCe3XsKTFxsDdedyHVj4/Gqkh+it+7M70qdIdSEb7ozpf5bpe0OQlqHPExiCr4XcjskEIv2uYReNv//Ux+DuIjxHjJ1bWLN1K/xEZUncTKgZ7KDHQ4K0xiVu3SCzCHAmqpfgsyPEVKAtGkpXp80bAcOxC45WFAJe7+jfZAlA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=groXO1LE; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="groXO1LE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D53EE1F00A3A; Tue, 21 Jul 2026 15:48:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784648881; bh=o6IZiZePkecdeQ59NDz1Mctry95aBqe/mtn3TYU8yRw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=groXO1LEgI2aJOcZz6ThwmAK4zfk7D+IT9WRLGnWD44Tkf1WIWZC6VSB5ef1fbynR ryB0rL2y28uHTzM8DA8cNV2KODFc5kDCPTDib6ptd/6t5RFQK5naNXiMPDmBQjMNK6 EZFaOz+zLuoJR+Qaf1duXNp65cv/JVStnPI9W+/4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?C=C3=A1ssio=20Gabriel?= , Takashi Iwai , Sasha Levin Subject: [PATCH 7.1 0323/2077] ALSA: xen-front: Connect event channel after stream prepare Date: Tue, 21 Jul 2026 16:59:56 +0200 Message-ID: <20260721152600.295926651@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152552.646164743@linuxfoundation.org> References: <20260721152552.646164743@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cássio Gabriel [ Upstream commit 3624f0bd4af15a820b1bd88b489980fa9fd61b7a ] The request channel must be connected from ALSA .open(), because hw-rule queries and the stream open request use it. The event channel is different: XENSND_EVT_CUR_POS handling uses ALSA runtime buffer and period geometry, and the corresponding Xen stream parameters are not submitted to the backend until .prepare() sends XENSND_OP_OPEN. Currently .open() connects both channels. A backend current-position event, or a stale event queued for an earlier stream instance, can therefore reach xen_snd_front_alsa_handle_cur_pos() before runtime->buffer_size and runtime->period_size are valid. Add a per-channel connection helper, connect only the request channel in .open(), connect the event channel after a successful stream prepare, and disconnect it before stream close/free. Re-check the event-channel state after taking ring_io_lock so disconnecting the event channel synchronizes against a threaded IRQ that passed the initial lockless state test. Keep defensive runtime geometry checks in the position handler. Fixes: 1cee559351a7 ("ALSA: xen-front: Implement ALSA virtual sound driver") Signed-off-by: Cássio Gabriel Link: https://patch.msgid.link/20260526-alsa-xen-event-channel-fixes-v1-2-91d3a6a50778@gmail.com Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/xen/xen_snd_front_alsa.c | 17 ++++++++++++----- sound/xen/xen_snd_front_evtchnl.c | 20 +++++++++++++------- sound/xen/xen_snd_front_evtchnl.h | 2 ++ 3 files changed, 27 insertions(+), 12 deletions(-) diff --git a/sound/xen/xen_snd_front_alsa.c b/sound/xen/xen_snd_front_alsa.c index dc626480123acd..a6dd196f73d662 100644 --- a/sound/xen/xen_snd_front_alsa.c +++ b/sound/xen/xen_snd_front_alsa.c @@ -378,7 +378,7 @@ static int alsa_open(struct snd_pcm_substream *substream) stream_clear(stream); - xen_snd_front_evtchnl_pair_set_connected(stream->evt_pair, true); + xen_snd_front_evtchnl_set_connected(&stream->evt_pair->req, true); ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT, alsa_hw_rule, stream, @@ -498,6 +498,8 @@ static int alsa_hw_free(struct snd_pcm_substream *substream) struct xen_snd_front_pcm_stream_info *stream = stream_get(substream); int ret; + xen_snd_front_evtchnl_set_connected(&stream->evt_pair->evt, false); + ret = xen_snd_front_stream_close(&stream->evt_pair->req); stream_free(stream); return ret; @@ -532,6 +534,7 @@ static int alsa_prepare(struct snd_pcm_substream *substream) return ret; stream->is_open = true; + xen_snd_front_evtchnl_set_connected(&stream->evt_pair->evt, true); } return 0; @@ -571,20 +574,24 @@ void xen_snd_front_alsa_handle_cur_pos(struct xen_snd_front_evtchnl *evtchnl, { struct snd_pcm_substream *substream = evtchnl->u.evt.substream; struct xen_snd_front_pcm_stream_info *stream = stream_get(substream); + struct snd_pcm_runtime *runtime = substream->runtime; snd_pcm_uframes_t delta, new_hw_ptr, cur_frame; - cur_frame = bytes_to_frames(substream->runtime, pos_bytes); + if (!runtime->buffer_size || !runtime->period_size) + return; + + cur_frame = bytes_to_frames(runtime, pos_bytes); delta = cur_frame - stream->be_cur_frame; stream->be_cur_frame = cur_frame; new_hw_ptr = (snd_pcm_uframes_t)atomic_read(&stream->hw_ptr); - new_hw_ptr = (new_hw_ptr + delta) % substream->runtime->buffer_size; + new_hw_ptr = (new_hw_ptr + delta) % runtime->buffer_size; atomic_set(&stream->hw_ptr, (int)new_hw_ptr); stream->out_frames += delta; - if (stream->out_frames > substream->runtime->period_size) { - stream->out_frames %= substream->runtime->period_size; + if (stream->out_frames > runtime->period_size) { + stream->out_frames %= runtime->period_size; snd_pcm_period_elapsed(substream); } } diff --git a/sound/xen/xen_snd_front_evtchnl.c b/sound/xen/xen_snd_front_evtchnl.c index 09e4c1d0563632..17a30452c0cca3 100644 --- a/sound/xen/xen_snd_front_evtchnl.c +++ b/sound/xen/xen_snd_front_evtchnl.c @@ -94,6 +94,9 @@ static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id) guard(mutex)(&channel->ring_io_lock); + if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED)) + return IRQ_HANDLED; + prod = page->in_prod; /* Ensure we see ring contents up to prod. */ virt_rmb(); @@ -430,8 +433,8 @@ int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info) return ret; } -void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair, - bool is_connected) +void xen_snd_front_evtchnl_set_connected(struct xen_snd_front_evtchnl *channel, + bool is_connected) { enum xen_snd_front_evtchnl_state state; @@ -440,13 +443,16 @@ void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair else state = EVTCHNL_STATE_DISCONNECTED; - scoped_guard(mutex, &evt_pair->req.ring_io_lock) { - evt_pair->req.state = state; + scoped_guard(mutex, &channel->ring_io_lock) { + channel->state = state; } +} - scoped_guard(mutex, &evt_pair->evt.ring_io_lock) { - evt_pair->evt.state = state; - } +void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair, + bool is_connected) +{ + xen_snd_front_evtchnl_set_connected(&evt_pair->req, is_connected); + xen_snd_front_evtchnl_set_connected(&evt_pair->evt, is_connected); } void xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair *evt_pair) diff --git a/sound/xen/xen_snd_front_evtchnl.h b/sound/xen/xen_snd_front_evtchnl.h index 8400261ac46601..f6ebdb09c0298c 100644 --- a/sound/xen/xen_snd_front_evtchnl.h +++ b/sound/xen/xen_snd_front_evtchnl.h @@ -77,6 +77,8 @@ void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info); int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info); void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *evtchnl); +void xen_snd_front_evtchnl_set_connected(struct xen_snd_front_evtchnl *channel, + bool is_connected); void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair, bool is_connected); -- 2.53.0