Re: [PATCH] drm: omapdrm: Do not use helper unininitialized in omap_fbdev_init()

[Tomi Valkeinen]

On 27/02/2023 11:01, Thomas Zimmermann wrote:
> Hi
>
> Am 24.02.23 um 18:25 schrieb Nathan Chancellor:
> > Clang warns (or errors with CONFIG_WERROR):
> >
> >    ../drivers/gpu/drm/omapdrm/omap_fbdev.c:235:6: error: variable 
> > 'helper' is used uninitialized whenever 'if' condition is true 
> > [-Werror,-Wsometimes-uninitialized]
> >            if (!fbdev)
> >                ^~~~~~
> >    ../drivers/gpu/drm/omapdrm/omap_fbdev.c:259:26: note: uninitialized 
> > use occurs here
> >            drm_fb_helper_unprepare(helper);
> >                                    ^~~~~~
> >    ../drivers/gpu/drm/omapdrm/omap_fbdev.c:235:2: note: remove the 
> > 'if' if its condition is always false
> >            if (!fbdev)
> >            ^~~~~~~~~~~
> >    ../drivers/gpu/drm/omapdrm/omap_fbdev.c:228:30: note: initialize 
> > the variable 'helper' to silence this warning
> >            struct drm_fb_helper *helper;
> >                                        ^
> >                                         = NULL
> >    1 error generated.
> >
> > Return early, as there is nothing for the function to do if memory
> > cannot be allocated. There is no point in adding another label to just
> > emit the warning at the end of the function in this case, as memory
> > allocation failures are already logged.
> >
> > Fixes: 3fb1f62f80a1 ("drm/fb-helper: Remove drm_fb_helper_unprepare() 
> > from drm_fb_helper_fini()")
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1809
> > Link: 
> > https://lore.kernel.org/oe-kbuild-all/202302250058.fYTe9aTP-lkp@xxxxxxxxx/
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
>
> Reviewed-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
>
> > ---
> > This is currently showing in mainline so I believe this should go to
> > drm-misc-next-fixes.
>
> This tree is only active from -rc6 to sometime during the merge window. 
> I'll add your patch to drm-misc-fixes ASAP.

If it's not too late:

Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>

 Tomi