On 2019/11/20 9:08 下午, Alexander Shishkin wrote:
> Commit a753bfcfdb1f ("intel_th: Make the switch allocate its subdevices")
> factored out intel_th_subdevice_alloc() from intel_th_populate(), but got
> the error path wrong, resulting in two instances of a double put_device()
> on a freshly initialized, but not 'added' device.
>
> Fix this by only doing one put_device() in the error path.
>
> Signed-off-by: Alexander Shishkin <[email protected]>
> Fixes: a753bfcfdb1f ("intel_th: Make the switch allocate its subdevices")
> Reported-by: Wen Yang <[email protected]>
> Reviewed-by: Andy Shevchenko <[email protected]>
> Cc: [email protected] # v4.14+
> ---
> drivers/hwtracing/intel_th/core.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c
> index d5c1821b31c6..0dfd97bbde9e 100644
> --- a/drivers/hwtracing/intel_th/core.c
> +++ b/drivers/hwtracing/intel_th/core.c
> @@ -649,10 +649,8 @@ intel_th_subdevice_alloc(struct intel_th *th,
> }
>
> err = intel_th_device_add_resources(thdev, res, subdev->nres);
> - if (err) {
> - put_device(&thdev->dev);
> + if (err)
> goto fail_put_device;
> - }
>
> if (subdev->type == INTEL_TH_OUTPUT) {
> if (subdev->mknode)
> @@ -667,10 +665,8 @@ intel_th_subdevice_alloc(struct intel_th *th,
> }
>
> err = device_add(&thdev->dev);
> - if (err) {
> - put_device(&thdev->dev);
> + if (err)
> goto fail_free_res;
> - }
>
> /* need switch driver to be loaded to enumerate the rest */
> if (subdev->type == INTEL_TH_SWITCH && !req) {
device_add() has increased the reference count,
so when it returns an error, an additional call to put_device()
is needed here to reduce the reference count.
--
Regards,
Wen
Wen Yang <[email protected]> writes:
> device_add() has increased the reference count,
>
> so when it returns an error, an additional call to put_device()
>
> is needed here to reduce the reference count.
No, in case of error it also drops its reference.
Regards,
--
Alex