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

[Jon Hunter <jonathanh@nvidia.com>]

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@nvidia.com>

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@arndb.de>
>>>
>>> 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@arndb.de>
>>> ---
>>>   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

-- 
nvpublic