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sound: usb: qmi: Prevent Null pointer deference due to connect/disconnect

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Currently the sound driver uses qmi workqueues for any qmi request
sequences to execute, however while doing fast disconnect/connect
there is a possbility that the worker thread race between each other
which might lead to a scenario where in between the connect sequence
the disconnect might interfere and the endpoint might get freed.
This might lead to a null pointer deferences in the process used by
the hcd.

Fix this by making use of the chip-s usage_count to serialize these
processes. The disconnect in card drvier will wait for the usage_count
to be decreased to 0 in order to execute the disconnect sequences
which woudl make sure that the connect runs completely before disconnect.

Change-Id: I2a996a5bd6a451fdffdd3d09ba62770e3779f3f4
Signed-off-by: Udipto Goswami <quic_ugoswami@quicinc.com>
Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
This commit is contained in:
Krishna Kurapati 2023-09-28 12:12:05 +05:30
parent 8e5bdd9685
commit 3b14c6f914
1 changed files with 3 additions and 1 deletions
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4
sound/usb/usb_audio_qmi_svc.c
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@ -1558,7 +1558,7 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle,
}
uadev[pcm_card_num].ctrl_intf = chip->ctrl_intf;
atomic_inc(&chip->usage_count);
if (req_msg->enable) {
ret = enable_audio_stream(subs,
map_pcm_format(req_msg->audio_format),
@ -1594,6 +1594,8 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle,
disable_audio_stream(subs);
}
atomic_dec(&chip->usage_count);
response:
if (!req_msg->enable && ret != -EINVAL && ret != -ENODEV) {
if (info_idx >= 0) {