build failure of next-20220818 due to 341dd1f7de4c ("wifi: rtw88: add the update channel flow to support setting by parameters")

build failure of next-20220818 due to 341dd1f7de4c ("wifi: rtw88: add the update channel flow to support setting by parameters")

[Sudip Mukherjee (Codethink)]

Hi All,

Not sure if it has been reported, clang builds of arm64 allmodconfig have
failed to build next-20220818 with the error:

drivers/net/wireless/realtek/rtw88/main.c:731:2: error: variable 'primary_channel_idx' is used uninitialized whenever switch default is taken [-Werror,-Wsometimes-uninitialized]
        default:
        ^~~~~~~
drivers/net/wireless/realtek/rtw88/main.c:754:39: note: uninitialized use occurs here
        hal->current_primary_channel_index = primary_channel_idx;
                                             ^~~~~~~~~~~~~~~~~~~

git bisect pointed to 341dd1f7de4c ("wifi: rtw88: add the update channel flow to support setting by parameters").
And, reverting that commit has fixed the build failure.

I will be happy to test any patch or provide any extra log if needed.


--
Regards
Sudip

Re: build failure of next-20220818 due to 341dd1f7de4c ("wifi: rtw88: add the update channel flow to support setting by parameters")

[Arnd Bergmann]

On Thu, Aug 18, 2022 at 1:40 PM Sudip Mukherjee (Codethink)
<sudipm.mukherjee@gmail.com> wrote:
>
> Hi All,
>
> Not sure if it has been reported, clang builds of arm64 allmodconfig have
> failed to build next-20220818 with the error:
>
> drivers/net/wireless/realtek/rtw88/main.c:731:2: error: variable 'primary_channel_idx' is used uninitialized whenever switch default is taken [-Werror,-Wsometimes-uninitialized]
>         default:
>         ^~~~~~~
> drivers/net/wireless/realtek/rtw88/main.c:754:39: note: uninitialized use occurs here
>         hal->current_primary_channel_index = primary_channel_idx;
>                                              ^~~~~~~~~~~~~~~~~~~
>
> git bisect pointed to 341dd1f7de4c ("wifi: rtw88: add the update channel flow to support setting by parameters").
> And, reverting that commit has fixed the build failure.
>
> I will be happy to test any patch or provide any extra log if needed.

Hi Sudeep,

in my experience, you get the best results by posting a patch instead
of a bug report
when you spot a new warning. If you are unsure it's the right fix,
just state that
in the description. The maintainers will then either be able to just
pick it up if
it looks correct, or be motivated to do a better patch if they don't
like it. ;-)

In this case, I think the best fix would be to merged the 'default'
with the 'case
RTW_CHANNEL_WIDTH_20' in the switch statement, and use
RTW_SC_DONT_CARE. Of course, I have no idea if that is the right fix,
but it would make sense.

Just try to avoid adding initializations to the variable declaration, as that
would prevent the compiler from warning if there is a new uninitialized use.

       Arnd

Re: build failure of next-20220818 due to 341dd1f7de4c ("wifi: rtw88: add the update channel flow to support setting by parameters")

[Arnd Bergmann]

On Thu, Aug 18, 2022 at 1:56 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> Hi Sudeep,
>

Sorry Sudip for misspelling your name...

       Arnd

Re: build failure of next-20220818 due to 341dd1f7de4c ("wifi: rtw88: add the update channel flow to support setting by parameters")

[Ping-Ke Shih]

On Thu, 2022-08-18 at 13:56 +0200, Arnd Bergmann wrote:
> On Thu, Aug 18, 2022 at 1:40 PM Sudip Mukherjee (Codethink)
> <sudipm.mukherjee@gmail.com> wrote:
> > Hi All,
> > 
> > Not sure if it has been reported, clang builds of arm64 allmodconfig have
> > failed to build next-20220818 with the error:
> > 
> > drivers/net/wireless/realtek/rtw88/main.c:731:2: error: variable 'primary_channel_idx' is used
> > uninitialized whenever switch default is taken [-Werror,-Wsometimes-uninitialized]
> >         default:
> >         ^~~~~~~
> > drivers/net/wireless/realtek/rtw88/main.c:754:39: note: uninitialized use occurs here
> >         hal->current_primary_channel_index = primary_channel_idx;
> >                                              ^~~~~~~~~~~~~~~~~~~
> > 
> > git bisect pointed to 341dd1f7de4c ("wifi: rtw88: add the update channel flow to support setting
> > by parameters").
> > And, reverting that commit has fixed the build failure.
> > 
> > I will be happy to test any patch or provide any extra log if needed.
> 
> Hi Sudeep,
> 
> in my experience, you get the best results by posting a patch instead
> of a bug report
> when you spot a new warning. If you are unsure it's the right fix,
> just state that
> in the description. The maintainers will then either be able to just
> pick it up if
> it looks correct, or be motivated to do a better patch if they don't
> like it. ;-)
> 
> In this case, I think the best fix would be to merged the 'default'
> with the 'case
> RTW_CHANNEL_WIDTH_20' in the switch statement, and use
> RTW_SC_DONT_CARE. Of course, I have no idea if that is the right fix,
> but it would make sense.
> 
> Just try to avoid adding initializations to the variable declaration, as that
> would prevent the compiler from warning if there is a new uninitialized use.
> 

I have sent a patch to fix this: 
https://lore.kernel.org/linux-wireless/20220815062004.22920-1-pkshih@realtek.com/T/#u

Ping-Ke