[PATCH] drm/i915: fix compilation warnings on maybe uninitialized pointers

[PATCH] drm/i915: fix compilation warnings on maybe uninitialized pointers

[Jérémy Lefaure]

Two warnings are produced by gcc (tested with gcc 6.2.1):

drivers/gpu/drm/i915/intel_csr.c: In function ‘csr_load_work_fn’:
drivers/gpu/drm/i915/intel_csr.c:400:5: error: ‘fw’ is used
uninitialized in this function [-Werror=uninitialized]
  if (fw)
       ^
and

In file included from drivers/gpu/drm/i915/i915_drv.h:47:0,
                 from drivers/gpu/drm/i915/intel_guc_loader.c:30:
drivers/gpu/drm/i915/intel_guc_loader.c: In function ‘intel_guc_init’:
./include/drm/drmP.h:228:2: error: ‘fw’ may be used uninitialized in this
function  -Werror=maybe-uninitialized]
  drm_printk(KERN_DEBUG, DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
  ^~~~~~~~~~
drivers/gpu/drm/i915/intel_guc_loader.c:595:25: note: ‘fw’ was declared here
  const struct firmware *fw;
                         ^~

When CONFIG_DRM_I915_WERROR is set, those warnings break the build.

Initializing fw pointer to NULL in both cases removes the warnings.

Signed-off-by: Jérémy Lefaure <jeremy.lefaure@lse.epita.fr>
---
 drivers/gpu/drm/i915/intel_csr.c        | 2 +-
 drivers/gpu/drm/i915/intel_guc_loader.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_csr.c b/drivers/gpu/drm/i915/intel_csr.c
index d7a04bc..3520b3c 100644
--- a/drivers/gpu/drm/i915/intel_csr.c
+++ b/drivers/gpu/drm/i915/intel_csr.c
@@ -389,7 +389,7 @@ static void csr_load_work_fn(struct work_struct *work)
 {
 	struct drm_i915_private *dev_priv;
 	struct intel_csr *csr;
-	const struct firmware *fw;
+	const struct firmware *fw = NULL;
 	int ret;
 
 	dev_priv = container_of(work, typeof(*dev_priv), csr.work);
diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
index 34d6ad2..ecfee49 100644
--- a/drivers/gpu/drm/i915/intel_guc_loader.c
+++ b/drivers/gpu/drm/i915/intel_guc_loader.c
@@ -592,7 +592,7 @@ static void guc_fw_fetch(struct drm_device *dev, struct intel_guc_fw *guc_fw)
 {
 	struct pci_dev *pdev = dev->pdev;
 	struct drm_i915_gem_object *obj;
-	const struct firmware *fw;
+	const struct firmware *fw = NULL;
 	struct guc_css_header *css;
 	size_t size;
 	int err;
-- 
2.10.2

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✓ Fi.CI.BAT: success for drm/i915: fix compilation warnings on maybe uninitialized pointers

[Patchwork]

== Series Details ==

Series: drm/i915: fix compilation warnings on maybe uninitialized pointers
URL   : https://patchwork.freedesktop.org/series/16061/
State : success

== Summary ==

Series 16061v1 drm/i915: fix compilation warnings on maybe uninitialized pointers
https://patchwork.freedesktop.org/api/1.0/series/16061/revisions/1/mbox/


fi-bdw-5557u     total:245  pass:230  dwarn:0   dfail:0   fail:0   skip:15 
fi-byt-n2820     total:245  pass:213  dwarn:0   dfail:0   fail:0   skip:32 
fi-ilk-650       total:245  pass:192  dwarn:0   dfail:0   fail:0   skip:53 
fi-skl-6260u     total:245  pass:231  dwarn:0   dfail:0   fail:0   skip:14 
fi-skl-6700k     total:245  pass:223  dwarn:1   dfail:0   fail:0   skip:21 
fi-snb-2520m     total:245  pass:213  dwarn:0   dfail:0   fail:0   skip:32 

477cc06f6ef4842fd63e28ff30d721462af199a6 drm-tip: 2016y-11m-28d-16h-17m-39s UTC integration manifest
adeefab drm/i915: fix compilation warnings on maybe uninitialized pointers

== Logs ==

For more details see: https://intel-gfx-ci.01.org/CI/Patchwork_3130/
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Re: [Intel-gfx] [PATCH] drm/i915: fix compilation warnings on maybe uninitialized pointers

[Daniel Vetter]

On Mon, Nov 28, 2016 at 06:43:19PM -0500, Jérémy Lefaure wrote:
> Two warnings are produced by gcc (tested with gcc 6.2.1):
> 
> drivers/gpu/drm/i915/intel_csr.c: In function ‘csr_load_work_fn’:
> drivers/gpu/drm/i915/intel_csr.c:400:5: error: ‘fw’ is used
> uninitialized in this function [-Werror=uninitialized]
>   if (fw)
>        ^
> and
> 
> In file included from drivers/gpu/drm/i915/i915_drv.h:47:0,
>                  from drivers/gpu/drm/i915/intel_guc_loader.c:30:
> drivers/gpu/drm/i915/intel_guc_loader.c: In function ‘intel_guc_init’:
> ./include/drm/drmP.h:228:2: error: ‘fw’ may be used uninitialized in this
> function  -Werror=maybe-uninitialized]
>   drm_printk(KERN_DEBUG, DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
>   ^~~~~~~~~~
> drivers/gpu/drm/i915/intel_guc_loader.c:595:25: note: ‘fw’ was declared here
>   const struct firmware *fw;
>                          ^~
> 
> When CONFIG_DRM_I915_WERROR is set, those warnings break the build.
> 
> Initializing fw pointer to NULL in both cases removes the warnings.
> 
> Signed-off-by: Jérémy Lefaure <jeremy.lefaure@lse.epita.fr>

Queued for -next, thanks for the patch.
-Daniel

> ---
>  drivers/gpu/drm/i915/intel_csr.c        | 2 +-
>  drivers/gpu/drm/i915/intel_guc_loader.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_csr.c b/drivers/gpu/drm/i915/intel_csr.c
> index d7a04bc..3520b3c 100644
> --- a/drivers/gpu/drm/i915/intel_csr.c
> +++ b/drivers/gpu/drm/i915/intel_csr.c
> @@ -389,7 +389,7 @@ static void csr_load_work_fn(struct work_struct *work)
>  {
>  	struct drm_i915_private *dev_priv;
>  	struct intel_csr *csr;
> -	const struct firmware *fw;
> +	const struct firmware *fw = NULL;
>  	int ret;
>  
>  	dev_priv = container_of(work, typeof(*dev_priv), csr.work);
> diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
> index 34d6ad2..ecfee49 100644
> --- a/drivers/gpu/drm/i915/intel_guc_loader.c
> +++ b/drivers/gpu/drm/i915/intel_guc_loader.c
> @@ -592,7 +592,7 @@ static void guc_fw_fetch(struct drm_device *dev, struct intel_guc_fw *guc_fw)
>  {
>  	struct pci_dev *pdev = dev->pdev;
>  	struct drm_i915_gem_object *obj;
> -	const struct firmware *fw;
> +	const struct firmware *fw = NULL;
>  	struct guc_css_header *css;
>  	size_t size;
>  	int err;
> -- 
> 2.10.2
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [PATCH] drm/i915: fix compilation warnings on maybe uninitialized pointers

[Tvrtko Ursulin]

On 29/11/2016 08:56, Daniel Vetter wrote:
> On Mon, Nov 28, 2016 at 06:43:19PM -0500, Jérémy Lefaure wrote:
>> Two warnings are produced by gcc (tested with gcc 6.2.1):
>>
>> drivers/gpu/drm/i915/intel_csr.c: In function ‘csr_load_work_fn’:
>> drivers/gpu/drm/i915/intel_csr.c:400:5: error: ‘fw’ is used
>> uninitialized in this function [-Werror=uninitialized]
>>   if (fw)
>>        ^
>> and
>>
>> In file included from drivers/gpu/drm/i915/i915_drv.h:47:0,
>>                  from drivers/gpu/drm/i915/intel_guc_loader.c:30:
>> drivers/gpu/drm/i915/intel_guc_loader.c: In function ‘intel_guc_init’:
>> ./include/drm/drmP.h:228:2: error: ‘fw’ may be used uninitialized in this
>> function  -Werror=maybe-uninitialized]
>>   drm_printk(KERN_DEBUG, DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
>>   ^~~~~~~~~~
>> drivers/gpu/drm/i915/intel_guc_loader.c:595:25: note: ‘fw’ was declared here
>>   const struct firmware *fw;
>>                          ^~
>>
>> When CONFIG_DRM_I915_WERROR is set, those warnings break the build.
>>
>> Initializing fw pointer to NULL in both cases removes the warnings.
>>
>> Signed-off-by: Jérémy Lefaure <jeremy.lefaure@lse.epita.fr>
>
> Queued for -next, thanks for the patch.

I just wanted to reply with two things; first who can figure out why 
this hasn't been picked up by the compiler before? Or why GCC 6.2.1 on 
my machine does not complain? Looks like a real mystery!

And secondly the csr loader is not even checking the return code. I was 
about to suggest a v2 but never mind now. Can do it myself.

Regards,

Tvrtko

> -Daniel
>
>> ---
>>  drivers/gpu/drm/i915/intel_csr.c        | 2 +-
>>  drivers/gpu/drm/i915/intel_guc_loader.c | 2 +-
>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_csr.c b/drivers/gpu/drm/i915/intel_csr.c
>> index d7a04bc..3520b3c 100644
>> --- a/drivers/gpu/drm/i915/intel_csr.c
>> +++ b/drivers/gpu/drm/i915/intel_csr.c
>> @@ -389,7 +389,7 @@ static void csr_load_work_fn(struct work_struct *work)
>>  {
>>  	struct drm_i915_private *dev_priv;
>>  	struct intel_csr *csr;
>> -	const struct firmware *fw;
>> +	const struct firmware *fw = NULL;
>>  	int ret;
>>
>>  	dev_priv = container_of(work, typeof(*dev_priv), csr.work);
>> diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
>> index 34d6ad2..ecfee49 100644
>> --- a/drivers/gpu/drm/i915/intel_guc_loader.c
>> +++ b/drivers/gpu/drm/i915/intel_guc_loader.c
>> @@ -592,7 +592,7 @@ static void guc_fw_fetch(struct drm_device *dev, struct intel_guc_fw *guc_fw)
>>  {
>>  	struct pci_dev *pdev = dev->pdev;
>>  	struct drm_i915_gem_object *obj;
>> -	const struct firmware *fw;
>> +	const struct firmware *fw = NULL;
>>  	struct guc_css_header *css;
>>  	size_t size;
>>  	int err;
>> --
>> 2.10.2
>>
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
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✓ Fi.CI.BAT: success for drm/i915: fix compilation warnings on maybe uninitialized pointers

[Patchwork]

== Series Details ==

Series: drm/i915: fix compilation warnings on maybe uninitialized pointers
URL   : https://patchwork.freedesktop.org/series/16061/
State : success

== Summary ==

Series 16061v1 drm/i915: fix compilation warnings on maybe uninitialized pointers
https://patchwork.freedesktop.org/api/1.0/series/16061/revisions/1/mbox/


fi-bdw-5557u     total:245  pass:230  dwarn:0   dfail:0   fail:0   skip:15 
fi-bsw-n3050     total:245  pass:205  dwarn:0   dfail:0   fail:0   skip:40 
fi-bxt-t5700     total:245  pass:217  dwarn:0   dfail:0   fail:0   skip:28 
fi-byt-j1900     total:245  pass:217  dwarn:0   dfail:0   fail:0   skip:28 
fi-byt-n2820     total:245  pass:213  dwarn:0   dfail:0   fail:0   skip:32 
fi-hsw-4770      total:245  pass:225  dwarn:0   dfail:0   fail:0   skip:20 
fi-hsw-4770r     total:245  pass:225  dwarn:0   dfail:0   fail:0   skip:20 
fi-ilk-650       total:245  pass:192  dwarn:0   dfail:0   fail:0   skip:53 
fi-ivb-3520m     total:245  pass:223  dwarn:0   dfail:0   fail:0   skip:22 
fi-ivb-3770      total:245  pass:223  dwarn:0   dfail:0   fail:0   skip:22 
fi-kbl-7500u     total:245  pass:223  dwarn:0   dfail:0   fail:0   skip:22 
fi-skl-6260u     total:245  pass:231  dwarn:0   dfail:0   fail:0   skip:14 
fi-skl-6700hq    total:245  pass:224  dwarn:0   dfail:0   fail:0   skip:21 
fi-skl-6700k     total:245  pass:223  dwarn:1   dfail:0   fail:0   skip:21 
fi-skl-6770hq    total:245  pass:231  dwarn:0   dfail:0   fail:0   skip:14 
fi-snb-2520m     total:245  pass:213  dwarn:0   dfail:0   fail:0   skip:32 
fi-snb-2600      total:245  pass:212  dwarn:0   dfail:0   fail:0   skip:33 

bf8dfcdb45998f470c39ea7b89412a2edbd069db drm-tip: 2016y-11m-29d-09h-31m-06s UTC integration manifest
c6b8fb2 drm/i915: fix compilation warnings on maybe uninitialized pointers

== Logs ==

For more details see: https://intel-gfx-ci.01.org/CI/Patchwork_3134/
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