kernel/linux.git/sound/virtio, branch v5.15.210

sound/virtio: Fix cancel_sync warnings on uninitialized work_structs

2025-05-02T05:44:35+00:00

[ Upstream commit 3c7df2e27346eb40a0e86230db1ccab195c97cfe ] Betty reported hitting the following warning: [ 8.709131][ T221] WARNING: CPU: 2 PID: 221 at kernel/workqueue.c:4182 ... [ 8.713282][ T221] Call trace: [ 8.713365][ T221] __flush_work+0x8d0/0x914 [ 8.713468][ T221] __cancel_work_sync+0xac/0xfc [ 8.713570][ T221] cancel_work_sync+0x24/0x34 [ 8.713667][ T221] virtsnd_remove+0xa8/0xf8 [virtio_snd ab15f34d0dd772f6d11327e08a81d46dc9c36276] [ 8.713868][ T221] virtsnd_probe+0x48c/0x664 [virtio_snd ab15f34d0dd772f6d11327e08a81d46dc9c36276] [ 8.714035][ T221] virtio_dev_probe+0x28c/0x390 [ 8.714139][ T221] really_probe+0x1bc/0x4c8 ... It seems we're hitting the error path in virtsnd_probe(), which triggers a virtsnd_remove() which iterates over the substreams calling cancel_work_sync() on the elapsed_period work_struct. Looking at the code, from earlier in: virtsnd_probe()->virtsnd_build_devs()->virtsnd_pcm_parse_cfg() We set snd->nsubstreams, allocate the snd->substreams, and if we then hit an error on the info allocation or something in virtsnd_ctl_query_info() fails, we will exit without having initialized the elapsed_period work_struct. When that error path unwinds we then call virtsnd_remove() which as long as the substreams array is allocated, will iterate through calling cancel_work_sync() on the uninitialized work struct hitting this warning. Takashi Iwai suggested this fix, which initializes the substreams structure right after allocation, so that if we hit the error paths we avoid trying to cleanup uninitialized data. Note: I have not yet managed to reproduce the issue myself, so this patch has had limited testing. Feedback or thoughts would be appreciated! Cc: Anton Yakovlev Cc: "Michael S. Tsirkin" Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: virtualization@lists.linux.dev Cc: linux-sound@vger.kernel.org Cc: kernel-team@android.com Reported-by: Betty Zhou Suggested-by: Takashi Iwai Signed-off-by: John Stultz Message-Id: <20250116194114.3375616-1-jstultz@google.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

ALSA: virtio: fix kernel-doc

2021-04-27T06:39:39+00:00

make W=1 warning: sound/virtio/virtio_ctl_msg.c:70: warning: expecting prototype for virtsnd_ctl_msg_request(). Prototype was for virtsnd_ctl_msg_response() instead Signed-off-by: Pierre-Louis Bossart Link: https://lore.kernel.org/r/20210426213902.234711-1-pierre-louis.bossart@linux.intel.com Signed-off-by: Takashi Iwai

ALSA: virtio: use module_virtio_driver() to simplify the code

2021-04-12T10:15:34+00:00

module_virtio_driver() makes the code simpler by eliminating boilerplate code. Signed-off-by: Chen Huang Reviewed-by: Anton Yakovlev Link: https://lore.kernel.org/r/20210408125429.1158703-1-chenhuang5@huawei.com Signed-off-by: Takashi Iwai

ALSA: virtio: introduce device suspend/resume support

2021-03-07T08:08:39+00:00

All running PCM substreams are stopped on device suspend and restarted on device resume. Signed-off-by: Anton Yakovlev Link: https://lore.kernel.org/r/20210302164709.3142702-10-anton.yakovlev@opensynergy.com Signed-off-by: Takashi Iwai

ALSA: virtio: introduce PCM channel map support

2021-03-07T08:08:20+00:00

Enumerate all available PCM channel maps and create ALSA controls. Signed-off-by: Anton Yakovlev Link: https://lore.kernel.org/r/20210302164709.3142702-9-anton.yakovlev@opensynergy.com Signed-off-by: Takashi Iwai

ALSA: virtio: introduce jack support

2021-03-07T08:08:11+00:00

Enumerate all available jacks and create ALSA controls. At the moment jacks have a simple implementation and can only be used to receive notifications about a plugged in/out device. Signed-off-by: Anton Yakovlev Link: https://lore.kernel.org/r/20210302164709.3142702-8-anton.yakovlev@opensynergy.com Signed-off-by: Takashi Iwai

ALSA: virtio: PCM substream operators

2021-03-07T08:08:03+00:00

Introduce the operators required for the operation of substreams. Signed-off-by: Anton Yakovlev Link: https://lore.kernel.org/r/20210302164709.3142702-7-anton.yakovlev@opensynergy.com Signed-off-by: Takashi Iwai

ALSA: virtio: handling control and I/O messages for the PCM device

2021-03-07T08:07:44+00:00

The driver implements a message-based transport for I/O substream operations. Before the start of the substream, the hardware buffer is sliced into I/O messages, the number of which is equal to the current number of periods. The size of each message is equal to the current size of one period. I/O messages are organized in an ordered queue. The completion of the I/O message indicates an elapsed period (the only exception is the end of the stream for the capture substream). Upon completion, the message is automatically re-added to the end of the queue. Signed-off-by: Anton Yakovlev Link: https://lore.kernel.org/r/20210302164709.3142702-6-anton.yakovlev@opensynergy.com Signed-off-by: Takashi Iwai

ALSA: virtio: build PCM devices and substream hardware descriptors

2021-03-07T08:07:35+00:00

Like the HDA specification, the virtio sound device specification links PCM substreams, jacks and PCM channel maps into functional groups. For each discovered group, a PCM device is created, the number of which coincides with the group number. Introduce the module parameters for setting the hardware buffer parameters: pcm_buffer_ms [=160] pcm_periods_min [=2] pcm_periods_max [=16] pcm_period_ms_min [=10] pcm_period_ms_max [=80] Signed-off-by: Anton Yakovlev Link: https://lore.kernel.org/r/20210302164709.3142702-5-anton.yakovlev@opensynergy.com Signed-off-by: Takashi Iwai

ALSA: virtio: handling control messages

2021-03-07T08:07:27+00:00

The control queue can be used by different parts of the driver to send commands to the device. Control messages can be either synchronous or asynchronous. The lifetime of a message is controlled by a reference count. Introduce a module parameter to set the message completion timeout: msg_timeout_ms [=1000] Signed-off-by: Anton Yakovlev Link: https://lore.kernel.org/r/20210302164709.3142702-4-anton.yakovlev@opensynergy.com Signed-off-by: Takashi Iwai