LinuxLists.cc - [PATCH] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote

2024-04-12 13:52:30

Subject: [PATCH] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote_control()

2024-04-29 11:24:46

Subject: Re: [PATCH] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote_control()

On 2024/4/12 21:52, Zheng Yejian wrote:
> Infinite log printing occurs during fuzz test:
>
> rc rc1: DViCO FusionHDTV DVB-T USB (LGZ201) as ...
> ...
> dvb-usb: schedule remote query interval to 100 msecs.
> dvb-usb: DViCO FusionHDTV DVB-T USB (LGZ201) successfully initialized ...
> dvb-usb: bulk message failed: -22 (1/0)
> dvb-usb: bulk message failed: -22 (1/0)
> dvb-usb: bulk message failed: -22 (1/0)
> ...
> dvb-usb: bulk message failed: -22 (1/0)
>
> Looking into the codes, there is a loop in dvb_usb_read_remote_control(),
> that is in rc_core_dvb_usb_remote_init() create a work that will call
> dvb_usb_read_remote_control(), and this work will reschedule itself at
> 'rc_interval' intervals to recursively call dvb_usb_read_remote_control(),
> see following code snippet:
>
> rc_core_dvb_usb_remote_init() {
> ...
> INIT_DELAYED_WORK(&d->rc_query_work, dvb_usb_read_remote_control);
> schedule_delayed_work(&d->rc_query_work,
> msecs_to_jiffies(rc_interval));
> ...
> }
>
> dvb_usb_read_remote_control() {
> ...
> err = d->props.rc.core.rc_query(d);
> if (err)
> err(...) // Did not return even if query failed
> schedule_delayed_work(&d->rc_query_work,
> msecs_to_jiffies(rc_interval));
> }
>
> When the infinite log printing occurs, the query callback
> 'd->props.rc.core.rc_query' is cxusb_rc_query(). And the log is due to
> the failure of finding a valid 'generic_bulk_ctrl_endpoint'
> in usb_bulk_msg(), see following code snippet:
>
> cxusb_rc_query() {
> cxusb_ctrl_msg() {
> dvb_usb_generic_rw() {
> ret = usb_bulk_msg(d->udev, usb_sndbulkpipe(d->udev,
> d->props.generic_bulk_ctrl_endpoint),...);
> if (ret)
> err("bulk message failed: %d (%d/%d)",ret,wlen,actlen);
> ...
> }
> ...
> }
>
> By analyzing the corresponding USB descriptor, it shows that the
> bNumEndpoints is 0 in its interface descriptor, but
> the 'generic_bulk_ctrl_endpoint' is 1, that means user don't configure
> a valid endpoint for 'generic_bulk_ctrl_endpoint', therefore this
> 'invalid' USB device should be rejected before it calls into
> dvb_usb_read_remote_control().
>
> To fix it, iiuc, we can add endpoint check in dvb_usb_adapter_init().
>
> Signed-off-by: Zheng Yejian <[email protected]>
> ---
> drivers/media/usb/dvb-usb/dvb-usb-init.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> Hi, I'm not very familiar with USB driver, and I'm not sure the
> type check is appropriate or not here. Would be any device properties
> that allow 'generic_bulk_ctrl_endpoint' not being configured, or would
> it be configured late after init ? :)
>

Kindly ping :)
Hi, Mauro, would you mind taking a look at this code ?

--
Thanks,
Zheng Yejian

> diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
> index fbf58012becd..48e7b9fb93dd 100644
> --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
> +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
> @@ -104,6 +104,14 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
> * sometimes a timeout occurs, this helps
> */
> if (d->props.generic_bulk_ctrl_endpoint != 0) {
> + ret = usb_pipe_type_check(d->udev, usb_sndbulkpipe(d->udev,
> + d->props.generic_bulk_ctrl_endpoint));
> + if (ret)
> + goto frontend_init_err;
> + ret = usb_pipe_type_check(d->udev, usb_rcvbulkpipe(d->udev,
> + d->props.generic_bulk_ctrl_endpoint));
> + if (ret)
> + goto frontend_init_err;
> usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
> usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
> }

2024-04-30 08:04:25

by Sean Young

[permalink] [raw]

Subject: Re: [PATCH] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote_control()

On Mon, Apr 29, 2024 at 07:24:21PM +0800, Zheng Yejian wrote:
> On 2024/4/12 21:52, Zheng Yejian wrote:
> > Infinite log printing occurs during fuzz test:
> >
> > rc rc1: DViCO FusionHDTV DVB-T USB (LGZ201) as ...
> > ...
> > dvb-usb: schedule remote query interval to 100 msecs.
> > dvb-usb: DViCO FusionHDTV DVB-T USB (LGZ201) successfully initialized ...
> > dvb-usb: bulk message failed: -22 (1/0)
> > dvb-usb: bulk message failed: -22 (1/0)
> > dvb-usb: bulk message failed: -22 (1/0)
> > ...
> > dvb-usb: bulk message failed: -22 (1/0)
> >
> > Looking into the codes, there is a loop in dvb_usb_read_remote_control(),
> > that is in rc_core_dvb_usb_remote_init() create a work that will call
> > dvb_usb_read_remote_control(), and this work will reschedule itself at
> > 'rc_interval' intervals to recursively call dvb_usb_read_remote_control(),
> > see following code snippet:
> >
> > rc_core_dvb_usb_remote_init() {
> > ...
> > INIT_DELAYED_WORK(&d->rc_query_work, dvb_usb_read_remote_control);
> > schedule_delayed_work(&d->rc_query_work,
> > msecs_to_jiffies(rc_interval));
> > ...
> > }
> >
> > dvb_usb_read_remote_control() {
> > ...
> > err = d->props.rc.core.rc_query(d);
> > if (err)
> > err(...) // Did not return even if query failed
> > schedule_delayed_work(&d->rc_query_work,
> > msecs_to_jiffies(rc_interval));
> > }
> >
> > When the infinite log printing occurs, the query callback
> > 'd->props.rc.core.rc_query' is cxusb_rc_query(). And the log is due to
> > the failure of finding a valid 'generic_bulk_ctrl_endpoint'
> > in usb_bulk_msg(), see following code snippet:
> >
> > cxusb_rc_query() {
> > cxusb_ctrl_msg() {
> > dvb_usb_generic_rw() {
> > ret = usb_bulk_msg(d->udev, usb_sndbulkpipe(d->udev,
> > d->props.generic_bulk_ctrl_endpoint),...);
> > if (ret)
> > err("bulk message failed: %d (%d/%d)",ret,wlen,actlen);
> > ...
> > }
> > ...
> > }
> >
> > By analyzing the corresponding USB descriptor, it shows that the
> > bNumEndpoints is 0 in its interface descriptor, but
> > the 'generic_bulk_ctrl_endpoint' is 1, that means user don't configure
> > a valid endpoint for 'generic_bulk_ctrl_endpoint', therefore this
> > 'invalid' USB device should be rejected before it calls into
> > dvb_usb_read_remote_control().
> >
> > To fix it, iiuc, we can add endpoint check in dvb_usb_adapter_init().
> >
> > Signed-off-by: Zheng Yejian <[email protected]>
> > ---
> > drivers/media/usb/dvb-usb/dvb-usb-init.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > Hi, I'm not very familiar with USB driver, and I'm not sure the
> > type check is appropriate or not here. Would be any device properties
> > that allow 'generic_bulk_ctrl_endpoint' not being configured, or would
> > it be configured late after init ? :)
> >
>
> Kindly ping :)
> Hi, Mauro, would you mind taking a look at this code ?
>
> --
> Thanks,
> Zheng Yejian
>
> > diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
> > index fbf58012becd..48e7b9fb93dd 100644
> > --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
> > +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
> > @@ -104,6 +104,14 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
> > * sometimes a timeout occurs, this helps
> > */
> > if (d->props.generic_bulk_ctrl_endpoint != 0) {
> > + ret = usb_pipe_type_check(d->udev, usb_sndbulkpipe(d->udev,
> > + d->props.generic_bulk_ctrl_endpoint));
> > + if (ret)
> > + goto frontend_init_err;
> > + ret = usb_pipe_type_check(d->udev, usb_rcvbulkpipe(d->udev,
> > + d->props.generic_bulk_ctrl_endpoint));
> > + if (ret)
> > + goto frontend_init_err;
> > usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
> > usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
> > }
>

Thank you for your patch.

I think your change looks good. The only comment I have is that the same
check should be done for generic_bulk_ctrl_endpoint_response as well; the
usb_clear_halt() should be done as well, I think.

Thanks

Sean

2024-04-30 09:26:15

by Zheng Yejian

[permalink] [raw]

Subject: Re: [PATCH] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote_control()

On 2024/4/30 16:04, Sean Young wrote:
> On Mon, Apr 29, 2024 at 07:24:21PM +0800, Zheng Yejian wrote:
>> On 2024/4/12 21:52, Zheng Yejian wrote:
>>> Infinite log printing occurs during fuzz test:
>>>
>>> rc rc1: DViCO FusionHDTV DVB-T USB (LGZ201) as ...
>>> ...
>>> dvb-usb: schedule remote query interval to 100 msecs.
>>> dvb-usb: DViCO FusionHDTV DVB-T USB (LGZ201) successfully initialized ...
>>> dvb-usb: bulk message failed: -22 (1/0)
>>> dvb-usb: bulk message failed: -22 (1/0)
>>> dvb-usb: bulk message failed: -22 (1/0)
>>> ...
>>> dvb-usb: bulk message failed: -22 (1/0)
>>>
>>> Looking into the codes, there is a loop in dvb_usb_read_remote_control(),
>>> that is in rc_core_dvb_usb_remote_init() create a work that will call
>>> dvb_usb_read_remote_control(), and this work will reschedule itself at
>>> 'rc_interval' intervals to recursively call dvb_usb_read_remote_control(),
>>> see following code snippet:
>>>
>>> rc_core_dvb_usb_remote_init() {
>>> ...
>>> INIT_DELAYED_WORK(&d->rc_query_work, dvb_usb_read_remote_control);
>>> schedule_delayed_work(&d->rc_query_work,
>>> msecs_to_jiffies(rc_interval));
>>> ...
>>> }
>>>
>>> dvb_usb_read_remote_control() {
>>> ...
>>> err = d->props.rc.core.rc_query(d);
>>> if (err)
>>> err(...) // Did not return even if query failed
>>> schedule_delayed_work(&d->rc_query_work,
>>> msecs_to_jiffies(rc_interval));
>>> }
>>>
>>> When the infinite log printing occurs, the query callback
>>> 'd->props.rc.core.rc_query' is cxusb_rc_query(). And the log is due to
>>> the failure of finding a valid 'generic_bulk_ctrl_endpoint'
>>> in usb_bulk_msg(), see following code snippet:
>>>
>>> cxusb_rc_query() {
>>> cxusb_ctrl_msg() {
>>> dvb_usb_generic_rw() {
>>> ret = usb_bulk_msg(d->udev, usb_sndbulkpipe(d->udev,
>>> d->props.generic_bulk_ctrl_endpoint),...);
>>> if (ret)
>>> err("bulk message failed: %d (%d/%d)",ret,wlen,actlen);
>>> ...
>>> }
>>> ...
>>> }
>>>
>>> By analyzing the corresponding USB descriptor, it shows that the
>>> bNumEndpoints is 0 in its interface descriptor, but
>>> the 'generic_bulk_ctrl_endpoint' is 1, that means user don't configure
>>> a valid endpoint for 'generic_bulk_ctrl_endpoint', therefore this
>>> 'invalid' USB device should be rejected before it calls into
>>> dvb_usb_read_remote_control().
>>>
>>> To fix it, iiuc, we can add endpoint check in dvb_usb_adapter_init().
>>>
>>> Signed-off-by: Zheng Yejian <[email protected]>
>>> ---
>>> drivers/media/usb/dvb-usb/dvb-usb-init.c | 8 ++++++++
>>> 1 file changed, 8 insertions(+)
>>>
>>> Hi, I'm not very familiar with USB driver, and I'm not sure the
>>> type check is appropriate or not here. Would be any device properties
>>> that allow 'generic_bulk_ctrl_endpoint' not being configured, or would
>>> it be configured late after init ? :)
>>>
>>
>> Kindly ping :)
>> Hi, Mauro, would you mind taking a look at this code ?
>>
>> --
>> Thanks,
>> Zheng Yejian
>>
>>> diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
>>> index fbf58012becd..48e7b9fb93dd 100644
>>> --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
>>> +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
>>> @@ -104,6 +104,14 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
>>> * sometimes a timeout occurs, this helps
>>> */
>>> if (d->props.generic_bulk_ctrl_endpoint != 0) {
>>> + ret = usb_pipe_type_check(d->udev, usb_sndbulkpipe(d->udev,
>>> + d->props.generic_bulk_ctrl_endpoint));
>>> + if (ret)
>>> + goto frontend_init_err;
>>> + ret = usb_pipe_type_check(d->udev, usb_rcvbulkpipe(d->udev,
>>> + d->props.generic_bulk_ctrl_endpoint));
>>> + if (ret)
>>> + goto frontend_init_err;
>>> usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
>>> usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
>>> }
>>
>
> Thank you for your patch.
>
> I think your change looks good. The only comment I have is that the same
> check should be done for generic_bulk_ctrl_endpoint_response as well; the
> usb_clear_halt() should be done as well, I think.
>

Thanks for your suggestion!
Do you mean the following change? If it is ok, I'll send a v2!

diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
index fbf58012becd..2a8395d6373c 100644
--- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
+++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
@@ -23,6 +23,23 @@ static int dvb_usb_force_pid_filter_usage;
module_param_named(force_pid_filter_usage, dvb_usb_force_pid_filter_usage, int, 0444);
MODULE_PARM_DESC(force_pid_filter_usage, "force all dvb-usb-devices to use a PID filter, if any (default: 0).");

+static int dvb_usb_clear_halt(struct dvb_usb_device *d, u8 endpoint)
+{
+ if (endpoint) {
+ int ret;
+
+ ret = usb_pipe_type_check(d->udev, usb_sndbulkpipe(d->udev, endpoint));
+ if (ret)
+ return ret;
+ ret = usb_pipe_type_check(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
+ if (ret)
+ return ret;
+ usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, endpoint));
+ usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
+ }
+ return 0;
+}
+
static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
{
struct dvb_usb_adapter *adap;
@@ -103,10 +120,12 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
* when reloading the driver w/o replugging the device
* sometimes a timeout occurs, this helps
*/
- if (d->props.generic_bulk_ctrl_endpoint != 0) {
- usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
- usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
- }
+ ret = dvb_usb_clear_halt(d, d->props.generic_bulk_ctrl_endpoint);
+ if (ret)
+ goto frontend_init_err;
+ ret = dvb_usb_clear_halt(d, d->props.generic_bulk_ctrl_endpoint_response);
+ if (ret)
+ goto frontend_init_err;

return 0;

--
Thanks,
Zheng Yejian

> Thanks
>
> Sean

2024-04-30 09:39:30

by Sean Young

[permalink] [raw]

Subject: Re: [PATCH] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote_control()

On Tue, Apr 30, 2024 at 05:19:56PM +0800, Zheng Yejian wrote:
> Thanks for your suggestion!
> Do you mean the following change? If it is ok, I'll send a v2!
>
> diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
> index fbf58012becd..2a8395d6373c 100644
> --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
> +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
> @@ -23,6 +23,23 @@ static int dvb_usb_force_pid_filter_usage;
> module_param_named(force_pid_filter_usage, dvb_usb_force_pid_filter_usage, int, 0444);
> MODULE_PARM_DESC(force_pid_filter_usage, "force all dvb-usb-devices to use a PID filter, if any (default: 0).");
>
> +static int dvb_usb_clear_halt(struct dvb_usb_device *d, u8 endpoint)

I don't think this is a good function name; we are checking that the
endpoint is correct and also clearing halts.

How about: dvb_usb_check_bulk_endpoint()

Looks good otherwise

Sean

> +{
> + if (endpoint) {
> + int ret;
> +
> + ret = usb_pipe_type_check(d->udev, usb_sndbulkpipe(d->udev, endpoint));
> + if (ret)
> + return ret;
> + ret = usb_pipe_type_check(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
> + if (ret)
> + return ret;
> + usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, endpoint));
> + usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
> + }
> + return 0;
> +}
> +
> static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
> {
> struct dvb_usb_adapter *adap;
> @@ -103,10 +120,12 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
> * when reloading the driver w/o replugging the device
> * sometimes a timeout occurs, this helps
> */
> - if (d->props.generic_bulk_ctrl_endpoint != 0) {
> - usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
> - usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
> - }
> + ret = dvb_usb_clear_halt(d, d->props.generic_bulk_ctrl_endpoint);
> + if (ret)
> + goto frontend_init_err;
> + ret = dvb_usb_clear_halt(d, d->props.generic_bulk_ctrl_endpoint_response);
> + if (ret)
> + goto frontend_init_err;
>
> return 0;
>
> --
> Thanks,
> Zheng Yejian
>
> > Thanks
> >
> > Sean
>

2024-04-30 10:06:10

by Zheng Yejian

[permalink] [raw]

Subject: Re: [PATCH] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote_control()

On 2024/4/30 17:36, Sean Young wrote:
> On Tue, Apr 30, 2024 at 05:19:56PM +0800, Zheng Yejian wrote:
>> Thanks for your suggestion!
>> Do you mean the following change? If it is ok, I'll send a v2!
>>
>> diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
>> index fbf58012becd..2a8395d6373c 100644
>> --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
>> +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
>> @@ -23,6 +23,23 @@ static int dvb_usb_force_pid_filter_usage;
>> module_param_named(force_pid_filter_usage, dvb_usb_force_pid_filter_usage, int, 0444);
>> MODULE_PARM_DESC(force_pid_filter_usage, "force all dvb-usb-devices to use a PID filter, if any (default: 0).");
>>
>> +static int dvb_usb_clear_halt(struct dvb_usb_device *d, u8 endpoint)
>
> I don't think this is a good function name; we are checking that the
> endpoint is correct and also clearing halts.
>
> How about: dvb_usb_check_bulk_endpoint()

Sure, I'll do it in v2!

--
Thank,
Zheng Yejian

>
> Looks good otherwise
>
> Sean
>
>> +{
>> + if (endpoint) {
>> + int ret;
>> +
>> + ret = usb_pipe_type_check(d->udev, usb_sndbulkpipe(d->udev, endpoint));
>> + if (ret)
>> + return ret;
>> + ret = usb_pipe_type_check(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
>> + if (ret)
>> + return ret;
>> + usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, endpoint));
>> + usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
>> + }
>> + return 0;
>> +}
>> +
>> static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
>> {
>> struct dvb_usb_adapter *adap;
>> @@ -103,10 +120,12 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
>> * when reloading the driver w/o replugging the device
>> * sometimes a timeout occurs, this helps
>> */
>> - if (d->props.generic_bulk_ctrl_endpoint != 0) {
>> - usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
>> - usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
>> - }
>> + ret = dvb_usb_clear_halt(d, d->props.generic_bulk_ctrl_endpoint);
>> + if (ret)
>> + goto frontend_init_err;
>> + ret = dvb_usb_clear_halt(d, d->props.generic_bulk_ctrl_endpoint_response);
>> + if (ret)
>> + goto frontend_init_err;
>>
>> return 0;
>>
>> --
>> Thanks,
>> Zheng Yejian
>>
>>> Thanks
>>>
>>> Sean
>>

2024-04-30 10:41:34

by Zheng Yejian

[permalink] [raw]

Subject: [PATCH v2] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote_control()

Infinite log printing occurs during fuzz test:

rc rc1: DViCO FusionHDTV DVB-T USB (LGZ201) as ...
...
dvb-usb: schedule remote query interval to 100 msecs.
dvb-usb: DViCO FusionHDTV DVB-T USB (LGZ201) successfully initialized ...
dvb-usb: bulk message failed: -22 (1/0)
dvb-usb: bulk message failed: -22 (1/0)
dvb-usb: bulk message failed: -22 (1/0)
...
dvb-usb: bulk message failed: -22 (1/0)

Looking into the codes, there is a loop in dvb_usb_read_remote_control(),
that is in rc_core_dvb_usb_remote_init() create a work that will call
dvb_usb_read_remote_control(), and this work will reschedule itself at
'rc_interval' intervals to recursively call dvb_usb_read_remote_control(),
see following code snippet:

rc_core_dvb_usb_remote_init() {
...
INIT_DELAYED_WORK(&d->rc_query_work, dvb_usb_read_remote_control);
schedule_delayed_work(&d->rc_query_work,
msecs_to_jiffies(rc_interval));
...
}

dvb_usb_read_remote_control() {
...
err = d->props.rc.core.rc_query(d);
if (err)
err(...) // Did not return even if query failed
schedule_delayed_work(&d->rc_query_work,
msecs_to_jiffies(rc_interval));
}

When the infinite log printing occurs, the query callback
'd->props.rc.core.rc_query' is cxusb_rc_query(). And the log is due to
the failure of finding a valid 'generic_bulk_ctrl_endpoint'
in usb_bulk_msg(), see following code snippet:

cxusb_rc_query() {
cxusb_ctrl_msg() {
dvb_usb_generic_rw() {
ret = usb_bulk_msg(d->udev, usb_sndbulkpipe(d->udev,
d->props.generic_bulk_ctrl_endpoint),...);
if (ret)
err("bulk message failed: %d (%d/%d)",ret,wlen,actlen);
...
}
...
}

By analyzing the corresponding USB descriptor, it shows that the
bNumEndpoints is 0 in its interface descriptor, but
the 'generic_bulk_ctrl_endpoint' is 1, that means user don't configure
a valid endpoint for 'generic_bulk_ctrl_endpoint', therefore this
'invalid' USB device should be rejected before it calls into
dvb_usb_read_remote_control().

To fix it, we need to add endpoint check for 'generic_bulk_ctrl_endpoint'.
And as Sean suggested, the same check and clear halts should be done for
'generic_bulk_ctrl_endpoint_response'. So introduce
dvb_usb_check_bulk_endpoint() to do it for both of them.

Fixes: 4d43e13f723e ("V4L/DVB (4643): Multi-input patch for DVB-USB device")
Signed-off-by: Zheng Yejian <[email protected]>
---
drivers/media/usb/dvb-usb/dvb-usb-init.c | 27 ++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)

v2:
- As Sean suggested, check endpoint and clear halt for both
'generic_bulk_ctrl_endpoint' and 'generic_bulk_ctrl_endpoint_response'
with the new introduced dvb_usb_check_bulk_endpoint();
Link: https://lore.kernel.org/all/[email protected]/
Link: https://lore.kernel.org/all/[email protected]/

- Add Fixes tag.

v1:
- Link: https://lore.kernel.org/all/[email protected]/

diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
index fbf58012becd..7eb321bab84f 100644
--- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
+++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
@@ -23,6 +23,23 @@ static int dvb_usb_force_pid_filter_usage;
module_param_named(force_pid_filter_usage, dvb_usb_force_pid_filter_usage, int, 0444);
MODULE_PARM_DESC(force_pid_filter_usage, "force all dvb-usb-devices to use a PID filter, if any (default: 0).");

+static int dvb_usb_check_bulk_endpoint(struct dvb_usb_device *d, u8 endpoint)
+{
+ if (endpoint) {
+ int ret;
+
+ ret = usb_pipe_type_check(d->udev, usb_sndbulkpipe(d->udev, endpoint));
+ if (ret)
+ return ret;
+ ret = usb_pipe_type_check(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
+ if (ret)
+ return ret;
+ usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, endpoint));
+ usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
+ }
+ return 0;
+}
+
static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
{
struct dvb_usb_adapter *adap;
@@ -103,10 +120,12 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
* when reloading the driver w/o replugging the device
* sometimes a timeout occurs, this helps
*/
- if (d->props.generic_bulk_ctrl_endpoint != 0) {
- usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
- usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
- }
+ ret = dvb_usb_check_bulk_endpoint(d, d->props.generic_bulk_ctrl_endpoint);
+ if (ret)
+ goto frontend_init_err;
+ ret = dvb_usb_check_bulk_endpoint(d, d->props.generic_bulk_ctrl_endpoint_response);
+ if (ret)
+ goto frontend_init_err;

return 0;

--
2.25.1

2024-05-03 11:51:26

by Sean Young

[permalink] [raw]

Subject: Re: [PATCH v2] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote_control()

On Tue, Apr 30, 2024 at 06:41:37PM +0800, Zheng Yejian wrote:
> Infinite log printing occurs during fuzz test:
>
> rc rc1: DViCO FusionHDTV DVB-T USB (LGZ201) as ...
> ...
> dvb-usb: schedule remote query interval to 100 msecs.
> dvb-usb: DViCO FusionHDTV DVB-T USB (LGZ201) successfully initialized ...
> dvb-usb: bulk message failed: -22 (1/0)
> dvb-usb: bulk message failed: -22 (1/0)
> dvb-usb: bulk message failed: -22 (1/0)
> ...
> dvb-usb: bulk message failed: -22 (1/0)
>
> Looking into the codes, there is a loop in dvb_usb_read_remote_control(),
> that is in rc_core_dvb_usb_remote_init() create a work that will call
> dvb_usb_read_remote_control(), and this work will reschedule itself at
> 'rc_interval' intervals to recursively call dvb_usb_read_remote_control(),
> see following code snippet:
>
> rc_core_dvb_usb_remote_init() {
> ...
> INIT_DELAYED_WORK(&d->rc_query_work, dvb_usb_read_remote_control);
> schedule_delayed_work(&d->rc_query_work,
> msecs_to_jiffies(rc_interval));
> ...
> }
>
> dvb_usb_read_remote_control() {
> ...
> err = d->props.rc.core.rc_query(d);
> if (err)
> err(...) // Did not return even if query failed
> schedule_delayed_work(&d->rc_query_work,
> msecs_to_jiffies(rc_interval));
> }
>
> When the infinite log printing occurs, the query callback
> 'd->props.rc.core.rc_query' is cxusb_rc_query(). And the log is due to
> the failure of finding a valid 'generic_bulk_ctrl_endpoint'
> in usb_bulk_msg(), see following code snippet:
>
> cxusb_rc_query() {
> cxusb_ctrl_msg() {
> dvb_usb_generic_rw() {
> ret = usb_bulk_msg(d->udev, usb_sndbulkpipe(d->udev,
> d->props.generic_bulk_ctrl_endpoint),...);
> if (ret)
> err("bulk message failed: %d (%d/%d)",ret,wlen,actlen);
> ...
> }
> ...
> }
>
> By analyzing the corresponding USB descriptor, it shows that the
> bNumEndpoints is 0 in its interface descriptor, but
> the 'generic_bulk_ctrl_endpoint' is 1, that means user don't configure
> a valid endpoint for 'generic_bulk_ctrl_endpoint', therefore this
> 'invalid' USB device should be rejected before it calls into
> dvb_usb_read_remote_control().
>
> To fix it, we need to add endpoint check for 'generic_bulk_ctrl_endpoint'.
> And as Sean suggested, the same check and clear halts should be done for
> 'generic_bulk_ctrl_endpoint_response'. So introduce
> dvb_usb_check_bulk_endpoint() to do it for both of them.
>
> Fixes: 4d43e13f723e ("V4L/DVB (4643): Multi-input patch for DVB-USB device")
> Signed-off-by: Zheng Yejian <[email protected]>
> ---
> drivers/media/usb/dvb-usb/dvb-usb-init.c | 27 ++++++++++++++++++++----
> 1 file changed, 23 insertions(+), 4 deletions(-)
>
> v2:
> - As Sean suggested, check endpoint and clear halt for both
> 'generic_bulk_ctrl_endpoint' and 'generic_bulk_ctrl_endpoint_response'
> with the new introduced dvb_usb_check_bulk_endpoint();
> Link: https://lore.kernel.org/all/[email protected]/
> Link: https://lore.kernel.org/all/[email protected]/
>
> - Add Fixes tag.
>
> v1:
> - Link: https://lore.kernel.org/all/[email protected]/
>
> diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
> index fbf58012becd..7eb321bab84f 100644
> --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
> +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
> @@ -23,6 +23,23 @@ static int dvb_usb_force_pid_filter_usage;
> module_param_named(force_pid_filter_usage, dvb_usb_force_pid_filter_usage, int, 0444);
> MODULE_PARM_DESC(force_pid_filter_usage, "force all dvb-usb-devices to use a PID filter, if any (default: 0).");
>
> +static int dvb_usb_check_bulk_endpoint(struct dvb_usb_device *d, u8 endpoint)
> +{
> + if (endpoint) {
> + int ret;
> +
> + ret = usb_pipe_type_check(d->udev, usb_sndbulkpipe(d->udev, endpoint));
> + if (ret)
> + return ret;
> + ret = usb_pipe_type_check(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
> + if (ret)
> + return ret;
> + usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, endpoint));
> + usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
> + }
> + return 0;
> +}
> +
> static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
> {
> struct dvb_usb_adapter *adap;
> @@ -103,10 +120,12 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
> * when reloading the driver w/o replugging the device
> * sometimes a timeout occurs, this helps
> */
> - if (d->props.generic_bulk_ctrl_endpoint != 0) {
> - usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
> - usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
> - }
> + ret = dvb_usb_check_bulk_endpoint(d, d->props.generic_bulk_ctrl_endpoint);
> + if (ret)
> + goto frontend_init_err;
> + ret = dvb_usb_check_bulk_endpoint(d, d->props.generic_bulk_ctrl_endpoint_response);
> + if (ret)
> + goto frontend_init_err;
>
> return 0;

This results in the following warning:

drivers/media/usb/dvb-usb/dvb-usb-init.c:133:9: warning: 'adap' may be used uninitialized [-Wmaybe-uninitialized]

I think these tests should be moved to the top of the function, so no cleanup
is required.

Sean

2024-05-09 12:44:41

by Zheng Yejian

[permalink] [raw]

Subject: [PATCH v3] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote_control()

Infinite log printing occurs during fuzz test:

rc rc1: DViCO FusionHDTV DVB-T USB (LGZ201) as ...
...
dvb-usb: schedule remote query interval to 100 msecs.
dvb-usb: DViCO FusionHDTV DVB-T USB (LGZ201) successfully initialized ...
dvb-usb: bulk message failed: -22 (1/0)
dvb-usb: bulk message failed: -22 (1/0)
dvb-usb: bulk message failed: -22 (1/0)
...
dvb-usb: bulk message failed: -22 (1/0)

Looking into the codes, there is a loop in dvb_usb_read_remote_control(),
that is in rc_core_dvb_usb_remote_init() create a work that will call
dvb_usb_read_remote_control(), and this work will reschedule itself at
'rc_interval' intervals to recursively call dvb_usb_read_remote_control(),
see following code snippet:

rc_core_dvb_usb_remote_init() {
...
INIT_DELAYED_WORK(&d->rc_query_work, dvb_usb_read_remote_control);
schedule_delayed_work(&d->rc_query_work,
msecs_to_jiffies(rc_interval));
...
}

dvb_usb_read_remote_control() {
...
err = d->props.rc.core.rc_query(d);
if (err)
err(...) // Did not return even if query failed
schedule_delayed_work(&d->rc_query_work,
msecs_to_jiffies(rc_interval));
}

When the infinite log printing occurs, the query callback
'd->props.rc.core.rc_query' is cxusb_rc_query(). And the log is due to
the failure of finding a valid 'generic_bulk_ctrl_endpoint'
in usb_bulk_msg(), see following code snippet:

cxusb_rc_query() {
cxusb_ctrl_msg() {
dvb_usb_generic_rw() {
ret = usb_bulk_msg(d->udev, usb_sndbulkpipe(d->udev,
d->props.generic_bulk_ctrl_endpoint),...);
if (ret)
err("bulk message failed: %d (%d/%d)",ret,wlen,actlen);
...
}
...
}

By analyzing the corresponding USB descriptor, it shows that the
bNumEndpoints is 0 in its interface descriptor, but
the 'generic_bulk_ctrl_endpoint' is 1, that means user don't configure
a valid endpoint for 'generic_bulk_ctrl_endpoint', therefore this
'invalid' USB device should be rejected before it calls into
dvb_usb_read_remote_control().

To fix it, we need to add endpoint check for 'generic_bulk_ctrl_endpoint'.
And as Sean suggested, the same check and clear halts should be done for
'generic_bulk_ctrl_endpoint_response'. So introduce
dvb_usb_check_bulk_endpoint() to do it for both of them.

Fixes: 4d43e13f723e ("V4L/DVB (4643): Multi-input patch for DVB-USB device")
Signed-off-by: Zheng Yejian <[email protected]>
---
drivers/media/usb/dvb-usb/dvb-usb-init.c | 35 +++++++++++++++++++++---
1 file changed, 31 insertions(+), 4 deletions(-)

v3:
- Fix following warning:
drivers/media/usb/dvb-usb/dvb-usb-init.c:133:9: warning: 'adap' may be used uninitialized [-Wmaybe-uninitialized]
Link: https://lore.kernel.org/all/[email protected]/

v2:
- As Sean suggested, check endpoint and clear halt for both
'generic_bulk_ctrl_endpoint' and 'generic_bulk_ctrl_endpoint_response'
with the new introduced dvb_usb_check_bulk_endpoint();
Link: https://lore.kernel.org/all/[email protected]/
Link: https://lore.kernel.org/all/[email protected]/
- Add Fixes tag.
- Link: https://lore.kernel.org/all/[email protected]/

v1:
- Link: https://lore.kernel.org/all/[email protected]/

diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
index fbf58012becd..22d83ac18eb7 100644
--- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
+++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
@@ -23,11 +23,40 @@ static int dvb_usb_force_pid_filter_usage;
module_param_named(force_pid_filter_usage, dvb_usb_force_pid_filter_usage, int, 0444);
MODULE_PARM_DESC(force_pid_filter_usage, "force all dvb-usb-devices to use a PID filter, if any (default: 0).");

+static int dvb_usb_check_bulk_endpoint(struct dvb_usb_device *d, u8 endpoint)
+{
+ if (endpoint) {
+ int ret;
+
+ ret = usb_pipe_type_check(d->udev, usb_sndbulkpipe(d->udev, endpoint));
+ if (ret)
+ return ret;
+ ret = usb_pipe_type_check(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
+ if (ret)
+ return ret;
+ }
+ return 0;
+}
+
+static void dvb_usb_clear_halt(struct dvb_usb_device *d, u8 endpoint)
+{
+ if (endpoint) {
+ usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, endpoint));
+ usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
+ }
+}
+
static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
{
struct dvb_usb_adapter *adap;
int ret, n, o;

+ ret = dvb_usb_check_bulk_endpoint(d, d->props.generic_bulk_ctrl_endpoint);
+ if (ret)
+ return ret;
+ ret = dvb_usb_check_bulk_endpoint(d, d->props.generic_bulk_ctrl_endpoint_response);
+ if (ret)
+ return ret;
for (n = 0; n < d->props.num_adapters; n++) {
adap = &d->adapter[n];
adap->dev = d;
@@ -103,10 +132,8 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
* when reloading the driver w/o replugging the device
* sometimes a timeout occurs, this helps
*/
- if (d->props.generic_bulk_ctrl_endpoint != 0) {
- usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
- usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
- }
+ dvb_usb_clear_halt(d, d->props.generic_bulk_ctrl_endpoint);
+ dvb_usb_clear_halt(d, d->props.generic_bulk_ctrl_endpoint_response);

return 0;

--
2.25.1

2024-05-27 08:27:30

by Zheng Yejian

[permalink] [raw]

Subject: Re: [PATCH v2] media: dvb-usb: Fix unexpected infinite loop in dvb_usb_read_remote_control()

On 2024/5/3 19:51, Sean Young wrote:
> On Tue, Apr 30, 2024 at 06:41:37PM +0800, Zheng Yejian wrote:
>> Infinite log printing occurs during fuzz test:
>>
>> rc rc1: DViCO FusionHDTV DVB-T USB (LGZ201) as ...
>> ...
>> dvb-usb: schedule remote query interval to 100 msecs.
>> dvb-usb: DViCO FusionHDTV DVB-T USB (LGZ201) successfully initialized ...
>> dvb-usb: bulk message failed: -22 (1/0)
>> dvb-usb: bulk message failed: -22 (1/0)
>> dvb-usb: bulk message failed: -22 (1/0)
>> ...
>> dvb-usb: bulk message failed: -22 (1/0)
>>
>> Looking into the codes, there is a loop in dvb_usb_read_remote_control(),
>> that is in rc_core_dvb_usb_remote_init() create a work that will call
>> dvb_usb_read_remote_control(), and this work will reschedule itself at
>> 'rc_interval' intervals to recursively call dvb_usb_read_remote_control(),
>> see following code snippet:
>>
>> rc_core_dvb_usb_remote_init() {
>> ...
>> INIT_DELAYED_WORK(&d->rc_query_work, dvb_usb_read_remote_control);
>> schedule_delayed_work(&d->rc_query_work,
>> msecs_to_jiffies(rc_interval));
>> ...
>> }
>>
>> dvb_usb_read_remote_control() {
>> ...
>> err = d->props.rc.core.rc_query(d);
>> if (err)
>> err(...) // Did not return even if query failed
>> schedule_delayed_work(&d->rc_query_work,
>> msecs_to_jiffies(rc_interval));
>> }
>>
>> When the infinite log printing occurs, the query callback
>> 'd->props.rc.core.rc_query' is cxusb_rc_query(). And the log is due to
>> the failure of finding a valid 'generic_bulk_ctrl_endpoint'
>> in usb_bulk_msg(), see following code snippet:
>>
>> cxusb_rc_query() {
>> cxusb_ctrl_msg() {
>> dvb_usb_generic_rw() {
>> ret = usb_bulk_msg(d->udev, usb_sndbulkpipe(d->udev,
>> d->props.generic_bulk_ctrl_endpoint),...);
>> if (ret)
>> err("bulk message failed: %d (%d/%d)",ret,wlen,actlen);
>> ...
>> }
>> ...
>> }
>>
>> By analyzing the corresponding USB descriptor, it shows that the
>> bNumEndpoints is 0 in its interface descriptor, but
>> the 'generic_bulk_ctrl_endpoint' is 1, that means user don't configure
>> a valid endpoint for 'generic_bulk_ctrl_endpoint', therefore this
>> 'invalid' USB device should be rejected before it calls into
>> dvb_usb_read_remote_control().
>>
>> To fix it, we need to add endpoint check for 'generic_bulk_ctrl_endpoint'.
>> And as Sean suggested, the same check and clear halts should be done for
>> 'generic_bulk_ctrl_endpoint_response'. So introduce
>> dvb_usb_check_bulk_endpoint() to do it for both of them.
>>
>> Fixes: 4d43e13f723e ("V4L/DVB (4643): Multi-input patch for DVB-USB device")
>> Signed-off-by: Zheng Yejian <[email protected]>
>> ---
>> drivers/media/usb/dvb-usb/dvb-usb-init.c | 27 ++++++++++++++++++++----
>> 1 file changed, 23 insertions(+), 4 deletions(-)
>>
>> v2:
>> - As Sean suggested, check endpoint and clear halt for both
>> 'generic_bulk_ctrl_endpoint' and 'generic_bulk_ctrl_endpoint_response'
>> with the new introduced dvb_usb_check_bulk_endpoint();
>> Link: https://lore.kernel.org/all/[email protected]/
>> Link: https://lore.kernel.org/all/[email protected]/
>>
>> - Add Fixes tag.
>>
>> v1:
>> - Link: https://lore.kernel.org/all/[email protected]/
>>
>> diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c
>> index fbf58012becd..7eb321bab84f 100644
>> --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c
>> +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c
>> @@ -23,6 +23,23 @@ static int dvb_usb_force_pid_filter_usage;
>> module_param_named(force_pid_filter_usage, dvb_usb_force_pid_filter_usage, int, 0444);
>> MODULE_PARM_DESC(force_pid_filter_usage, "force all dvb-usb-devices to use a PID filter, if any (default: 0).");
>>
>> +static int dvb_usb_check_bulk_endpoint(struct dvb_usb_device *d, u8 endpoint)
>> +{
>> + if (endpoint) {
>> + int ret;
>> +
>> + ret = usb_pipe_type_check(d->udev, usb_sndbulkpipe(d->udev, endpoint));
>> + if (ret)
>> + return ret;
>> + ret = usb_pipe_type_check(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
>> + if (ret)
>> + return ret;
>> + usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, endpoint));
>> + usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, endpoint));
>> + }
>> + return 0;
>> +}
>> +
>> static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
>> {
>> struct dvb_usb_adapter *adap;
>> @@ -103,10 +120,12 @@ static int dvb_usb_adapter_init(struct dvb_usb_device *d, short *adapter_nrs)
>> * when reloading the driver w/o replugging the device
>> * sometimes a timeout occurs, this helps
>> */
>> - if (d->props.generic_bulk_ctrl_endpoint != 0) {
>> - usb_clear_halt(d->udev, usb_sndbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
>> - usb_clear_halt(d->udev, usb_rcvbulkpipe(d->udev, d->props.generic_bulk_ctrl_endpoint));
>> - }
>> + ret = dvb_usb_check_bulk_endpoint(d, d->props.generic_bulk_ctrl_endpoint);
>> + if (ret)
>> + goto frontend_init_err;
>> + ret = dvb_usb_check_bulk_endpoint(d, d->props.generic_bulk_ctrl_endpoint_response);
>> + if (ret)
>> + goto frontend_init_err;
>>
>> return 0;
>
> This results in the following warning:
>
> drivers/media/usb/dvb-usb/dvb-usb-init.c:133:9: warning: 'adap' may be used uninitialized [-Wmaybe-uninitialized]
>
> I think these tests should be moved to the top of the function, so no cleanup
> is required.
>

Hi, Sean,

I have fixed the warning in v3: https://lore.kernel.org/all/[email protected]/,
would you mind taking a look at it ?
I introduce a new funciton dvb_usb_clear_halt() to clear sndbulkpipe and rcvbulkpipe,
dvb_usb_check_bulk_endpoint() only do pipe type check and is moved to the top of
the function.

--
Thanks,
Zheng Yejian

>
> Sean