Hi Hans,
Thank you for the patch.
On Fri, May 10, 2024 at 09:11:46AM +0200, Hans Verkuil wrote:
> This reverts commit 9801b5b28c6929139d6fceeee8d739cc67bb2739.
>
> This patch introduced a potential deadlock scenario:
>
> [Wed May 8 10:02:06 2024] Possible unsafe locking scenario:
>
> [Wed May 8 10:02:06 2024] CPU0 CPU1
> [Wed May 8 10:02:06 2024] ---- ----
> [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1620:(hdl_vid_cap)->_lock);
> [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1608:(hdl_user_vid)->_lock);
> [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1620:(hdl_vid_cap)->_lock);
> [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1608:(hdl_user_vid)->_lock);
>
> For now just revert.
>
> Fixes: 9801b5b28c69 ("media: v4l2-ctrls: show all owned controls in log_status")
> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-ctrls-core.c | 18 +++++-------------
> 1 file changed, 5 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> index c59dd691f79f6..eeab6a5eb7bac 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> @@ -2507,8 +2507,7 @@ int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl)
> EXPORT_SYMBOL(v4l2_ctrl_handler_setup);
>
> /* Log the control name and value */
> -static void log_ctrl(const struct v4l2_ctrl_handler *hdl,
> - struct v4l2_ctrl *ctrl,
> +static void log_ctrl(const struct v4l2_ctrl *ctrl,
> const char *prefix, const char *colon)
> {
> if (ctrl->flags & (V4L2_CTRL_FLAG_DISABLED | V4L2_CTRL_FLAG_WRITE_ONLY))
> @@ -2518,11 +2517,7 @@ static void log_ctrl(const struct v4l2_ctrl_handler *hdl,
>
> pr_info("%s%s%s: ", prefix, colon, ctrl->name);
>
> - if (ctrl->handler != hdl)
> - v4l2_ctrl_lock(ctrl);
> ctrl->type_ops->log(ctrl);
> - if (ctrl->handler != hdl)
> - v4l2_ctrl_unlock(ctrl);
>
> if (ctrl->flags & (V4L2_CTRL_FLAG_INACTIVE |
> V4L2_CTRL_FLAG_GRABBED |
> @@ -2541,7 +2536,7 @@ static void log_ctrl(const struct v4l2_ctrl_handler *hdl,
> void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
> const char *prefix)
> {
> - struct v4l2_ctrl_ref *ref;
> + struct v4l2_ctrl *ctrl;
> const char *colon = "";
> int len;
>
> @@ -2553,12 +2548,9 @@ void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
> if (len && prefix[len - 1] != ' ')
> colon = ": ";
> mutex_lock(hdl->lock);
> - list_for_each_entry(ref, &hdl->ctrl_refs, node) {
> - if (ref->from_other_dev ||
> - (ref->ctrl->flags & V4L2_CTRL_FLAG_DISABLED))
> - continue;
> - log_ctrl(hdl, ref->ctrl, prefix, colon);
> - }
> + list_for_each_entry(ctrl, &hdl->ctrls, node)
> + if (!(ctrl->flags & V4L2_CTRL_FLAG_DISABLED))
> + log_ctrl(ctrl, prefix, colon);
> mutex_unlock(hdl->lock);
> }
> EXPORT_SYMBOL(v4l2_ctrl_handler_log_status);
--
Regards,
Laurent Pinchart
