Em Wed, 22 Jul 2020 06:41:26 -0700
trix@xxxxxxxxxx escreveu:
> From: Tom Rix <trix@xxxxxxxxxx>
>
> Clang static analysis reports this error
>
> drivers/media/dvb-frontends/cxd2099.c:420:2: warning: Undefined
> or garbage value returned to caller
> return val;
> ^~~~~~~~~~
>
> In read_cam_control, the call to read_io can fail.
> When it fails val is not set.
>
> The failure status should be returned to the caller,
> not the unset val.
>
> Similar problem with read_attribute_mem
>
> Fixes: 0f0b270f905b ("[media] ngene: CXD2099AR Common Interface driver")
>
> Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
> ---
> drivers/media/dvb-frontends/cxd2099.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/dvb-frontends/cxd2099.c b/drivers/media/dvb-frontends/cxd2099.c
> index f88b5355493e..9dfaf18fc4b4 100644
> --- a/drivers/media/dvb-frontends/cxd2099.c
> +++ b/drivers/media/dvb-frontends/cxd2099.c
> @@ -387,12 +387,15 @@ static int read_attribute_mem(struct dvb_ca_en50221 *ca,
> {
> struct cxd *ci = ca->data;
> u8 val;
> + int ret;
>
> mutex_lock(&ci->lock);
> set_mode(ci, 1);
> - read_pccard(ci, address, &val, 1);
> + ret = read_pccard(ci, address, &val, 1);
> + if (!ret)
> + ret = val;
> mutex_unlock(&ci->lock);
> - return val;
> + return ret;
> }
>
> static int write_attribute_mem(struct dvb_ca_en50221 *ca, int slot,
> @@ -412,12 +415,15 @@ static int read_cam_control(struct dvb_ca_en50221 *ca,
> {
> struct cxd *ci = ca->data;
> unsigned int val;
> + int ret;
>
> mutex_lock(&ci->lock);
> set_mode(ci, 0);
> - read_io(ci, address, &val);
> + ret = read_io(ci, address, &val);
> + if (!ret)
> + ret = val;
> mutex_unlock(&ci->lock);
> - return val;
> + return ret;
> }
>
> static int write_cam_control(struct dvb_ca_en50221 *ca, int slot,
Hmm... Had you test this one on a real hardware? It is not
uncommon to have some DVB devices that would fail reading
when the firmware is on cold state.
Without testing a patch like that at a real hardware, there's
no way to know if this is intentional or if the original
developer forgot to add a check for the error.
So, at most, it could print some warning message for
non-zero return codes.
Thanks,
Mauro
