Is there a bug in dgnc.ko?

Is there a bug in dgnc.ko?

[Navy Cheng]

Hi,

My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
I change to *dir*/drivers/staging/dgnc and do like this:

    sudo insmod ./dgnc.ko
    sudo lsmod | grep dgnc
    sudo rmmod ./dgnc
    sudo insmod ./dgnc.ko

After I re-insmod the dgnc module, my laptop is breakdown.

My OS is debian 8.0. Is there a bug in dgnc.ko or something wrong with my
OS or kernel. If there is a bug, How can I find it?

Thanks.

Is there a bug in dgnc.ko?

[Valdis.Kletnieks at vt.edu]

On Wed, 24 Feb 2016 12:57:42 +0800, Navy Cheng said:
> Hi,
>
> My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> I change to *dir*/drivers/staging/dgnc and do like this:
>
>     sudo insmod ./dgnc.ko

What output, if any, did this generate?

>     sudo lsmod | grep dgnc

Again, what messages?

>     sudo rmmod ./dgnc

Again, what happened?

>     sudo insmod ./dgnc.ko

And here?

> After I re-insmod the dgnc module, my laptop is breakdown.

What does "breakdown" mean?  Did it hang entirely? Did you get a message
in your dmesg output and/or on the console?  Other?

> My OS is debian 8.0. Is there a bug in dgnc.ko or something wrong with my
> OS or kernel. If there is a bug, How can I find it?

Start by providing enough info to see if there's a bug.
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Is there a bug in dgnc.ko?

[Greg KH]

On Wed, Feb 24, 2016 at 12:57:42PM +0800, Navy Cheng wrote:
> Hi,
> 
> My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> I change to *dir*/drivers/staging/dgnc and do like this:
> 
>     sudo insmod ./dgnc.ko

Do you have the hardware that this driver controls?

>     sudo lsmod | grep dgnc

Does that show anything?

>     sudo rmmod ./dgnc
>     sudo insmod ./dgnc.ko
> 
> After I re-insmod the dgnc module, my laptop is breakdown.

Then there's a bug to fix in the driver, it must not clean up everything
properly.  Based on a quick read of it, there is lots of things that
need to be fixed in it, that's why it is in staging.  If you are
interested, I would suggest fixing this issue would be a great start.

good luck!

greg k-h

Is there a bug in dgnc.ko?

[Navy Cheng]

On Wed, Feb 24, 2016 at 12:37:40AM -0500, Valdis.Kletnieks at vt.edu wrote:
> On Wed, 24 Feb 2016 12:57:42 +0800, Navy Cheng said:
> > Hi,
> >
> > My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> > I change to *dir*/drivers/staging/dgnc and do like this:
> >
> >     sudo insmod ./dgnc.ko
> 
> What output, if any, did this generate?

No output. I use *dmesg* to find more information:

[  572.915977] dgnc: module is from the staging directory, the quality is
   	       unknown, you have been warned.

> >     sudo lsmod | grep dgnc
> 
> Again, what messages?

Output:
	dgnc                   65536  0

> >     sudo rmmod ./dgnc
> 
> Again, what happened?

No output. After *dmesg*, no more info in the ring buffer.

> >     sudo insmod ./dgnc.ko
> 
> And here?

No output. 


> > After I re-insmod the dgnc module, my laptop is breakdown.
>
> What does "breakdown" mean?  Did it hang entirely? Did you get a message
> in your dmesg output and/or on the console?  Other?

The GUI stop work and any key in my laptop is not work. The *Caps Lock lamp*
in the keyboard is flashing.

> > My OS is debian 8.0. Is there a bug in dgnc.ko or something wrong with my
> > OS or kernel. If there is a bug, How can I find it?
> 
> Start by providing enough info to see if there's a bug.



> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

Is there a bug in dgnc.ko?

[Navy Cheng]

On Tue, Feb 23, 2016 at 09:43:56PM -0800, Greg KH wrote:
> On Wed, Feb 24, 2016 at 12:57:42PM +0800, Navy Cheng wrote:
> > Hi,
> > 
> > My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> > I change to *dir*/drivers/staging/dgnc and do like this:
> > 
> >     sudo insmod ./dgnc.ko
> 
> Do you have the hardware that this driver controls?

I'm not sure. My laptop is Dell Inspiron 14R - 5437 and I don't know if
there is the right hardware. I often don't know about what a driver is used
for in drivers/staging/. Is there any good way to know the function of a
driver or module?

> 
> >     sudo lsmod | grep dgnc
> 
> Does that show anything?

Output: dgnc                   65536  0

> >     sudo rmmod ./dgnc
> >     sudo insmod ./dgnc.ko
> > 
> > After I re-insmod the dgnc module, my laptop is breakdown.
> 
> Then there's a bug to fix in the driver, it must not clean up everything
> properly.  Based on a quick read of it, there is lots of things that
> need to be fixed in it, that's why it is in staging.  If you are
> interested, I would suggest fixing this issue would be a great start.

I'm very glad to get your advice to fix this issue. As a kernelnewbies, I
have sent two patches about code cleaning to you, and they are merged to
the kernel tree. I realy interested to fix this bug to improve my
understanding of the kerenl.

Thank you.

Is there a bug in dgnc.ko?

[Sudip Mukherjee]

On Wed, Feb 24, 2016 at 5:27 PM, Navy Cheng <navych@126.com> wrote:
> On Tue, Feb 23, 2016 at 09:43:56PM -0800, Greg KH wrote:
>> On Wed, Feb 24, 2016 at 12:57:42PM +0800, Navy Cheng wrote:
>> > Hi,
>> >
>> > My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
>> > I change to *dir*/drivers/staging/dgnc and do like this:
>> >
>> >     sudo insmod ./dgnc.ko
>>
>> Do you have the hardware that this driver controls?
>
> I'm not sure. My laptop is Dell Inspiron 14R - 5437 and I don't know if
> there is the right hardware. I often don't know about what a driver is used
> for in drivers/staging/. Is there any good way to know the function of a
> driver or module?
>
>>
>> >     sudo lsmod | grep dgnc
>>
>> Does that show anything?
>
> Output: dgnc                   65536  0
>
>> >     sudo rmmod ./dgnc

what did dmesg showed after you did rmmod?

regards
sudip

Is there a bug in dgnc.ko?

[Greg KH]

On Wed, Feb 24, 2016 at 07:57:01PM +0800, Navy Cheng wrote:
> On Tue, Feb 23, 2016 at 09:43:56PM -0800, Greg KH wrote:
> > On Wed, Feb 24, 2016 at 12:57:42PM +0800, Navy Cheng wrote:
> > > Hi,
> > > 
> > > My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> > > I change to *dir*/drivers/staging/dgnc and do like this:
> > > 
> > >     sudo insmod ./dgnc.ko
> > 
> > Do you have the hardware that this driver controls?
> 
> I'm not sure. My laptop is Dell Inspiron 14R - 5437 and I don't know if
> there is the right hardware. I often don't know about what a driver is used
> for in drivers/staging/. Is there any good way to know the function of a
> driver or module?

If you don't think you have the hardware, then almost always, you don't
have the hardware, it's pretty simple :)

> > 
> > >     sudo lsmod | grep dgnc
> > 
> > Does that show anything?
> 
> Output: dgnc                   65536  0

Great, it loaded, then crashes when you unload, congratulations, you can
now work on fixing that bug!

good luck,

greg k-h

Is there a bug in dgnc.ko?

[Navy Cheng]

On Wed, Feb 24, 2016 at 05:33:11PM +0530, Sudip Mukherjee wrote:
> On Wed, Feb 24, 2016 at 5:27 PM, Navy Cheng <navych@126.com> wrote:
> > On Tue, Feb 23, 2016 at 09:43:56PM -0800, Greg KH wrote:
> >> On Wed, Feb 24, 2016 at 12:57:42PM +0800, Navy Cheng wrote:
> >> > Hi,
> >> >
> >> > My kernel version is v4.4, and I have built drivers/staging/dgnc/dgnc.ko.
> >> > I change to *dir*/drivers/staging/dgnc and do like this:
> >> >
> >> >     sudo insmod ./dgnc.ko
> >>
> >> Do you have the hardware that this driver controls?
> >
> > I'm not sure. My laptop is Dell Inspiron 14R - 5437 and I don't know if
> > there is the right hardware. I often don't know about what a driver is used
> > for in drivers/staging/. Is there any good way to know the function of a
> > driver or module?
> >
> >>
> >> >     sudo lsmod | grep dgnc
> >>
> >> Does that show anything?
> >
> > Output: dgnc                   65536  0
> >
> >> >     sudo rmmod ./dgnc
> 
> what did dmesg showed after you did rmmod?
> 

*dmesg* show nothing after I rmmod dgnc. I guess something wrong with
dgnc_cleanup_module() which is called when dgnc is removed.