Re: [PATCH] gpu: host1x: fix uninitialized variable use

[Jon Hunter]

On 08/03/2023 16:56, Nathan Chancellor wrote:
> Ping? This warning is now in 6.3-rc1.

Thierry is away at the moment.

David, Daniel, do you want to pick this up directly in the meantime as a 
fix for 6.3? Mikko has already reviewed and FWIW ...

Reviewed-by: Jon Hunter <jonathanh@xxxxxxxxxx>

Thanks
Jon


> On Thu, Feb 23, 2023 at 09:28:28AM -0700, Nathan Chancellor wrote:
> > Hi Thierry, Daniel, and David,
> >
> > On Fri, Jan 27, 2023 at 11:14:00PM +0100, Arnd Bergmann wrote:
> > > From: Arnd Bergmann <arnd@xxxxxxxx>
> > >
> > > The error handling for platform_get_irq() failing no longer
> > > works after a recent change, clang now points this out with
> > > a warning:
> > >
> > > drivers/gpu/host1x/dev.c:520:6: error: variable 'syncpt_irq' is uninitialized when used here [-Werror,-Wuninitialized]
> > >          if (syncpt_irq < 0)
> > >              ^~~~~~~~~~
> > >
> > > Fix this by removing the variable and checking the correct
> > > error status.
> > >
> > > Fixes: 625d4ffb438c ("gpu: host1x: Rewrite syncpoint interrupt handling")
> > > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> > > ---
> > >   drivers/gpu/host1x/dev.c | 5 ++---
> > >   1 file changed, 2 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
> > > index 4872d183d860..aae2efeef503 100644
> > > --- a/drivers/gpu/host1x/dev.c
> > > +++ b/drivers/gpu/host1x/dev.c
> > > @@ -487,7 +487,6 @@ static int host1x_get_resets(struct host1x *host)
> > >   static int host1x_probe(struct platform_device *pdev)
> > >   {
> > >   	struct host1x *host;
> > > -	int syncpt_irq;
> > >   	int err;
> > >   
> > >   	host = devm_kzalloc(&pdev->dev, sizeof(*host), GFP_KERNEL);
> > > @@ -517,8 +516,8 @@ static int host1x_probe(struct platform_device *pdev)
> > >   	}
> > >   
> > >   	host->syncpt_irq = platform_get_irq(pdev, 0);
> > > -	if (syncpt_irq < 0)
> > > -		return syncpt_irq;
> > > +	if (host->syncpt_irq < 0)
> > > +		return host->syncpt_irq;
> > >   
> > >   	mutex_init(&host->devices_lock);
> > >   	INIT_LIST_HEAD(&host->devices);
> > > --
> > > 2.39.0
> >
> > Apologies if this has been reported already or has a solution in
> > progress but mainline is now broken because this change got separated
> > from the change it is fixing:
> >
> > https://github.com/ClangBuiltLinux/continuous-integration2/actions/runs/4249931209/jobs/7391912774
> > https://storage.tuxsuite.com/public/clangbuiltlinux/continuous-integration2/builds/2M7y9HpiXB13qiC2mkHMyeZOcLW/build.log
> >
> > I see this change sitting in the drm-tegra tree [1], which is getting
> > merged into -next, so it is fixed there, which is why we did not notice
> > any issues until the drm-next tree was merged into mainline. Can this be
> > fast tracked to Linus to unbreak clang builds with -Werror?
> >
> > [1]: https://gitlab.freedesktop.org/drm/tegra/-/commit/b9930311641cf2ed905a84aabe27e8f3868aee4a

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