'id' is enum type like unsigned int, so it will never be less than zero.
Fixes: 4aaf448fa975 ("vga_switcheroo: set audio client id according to bound GPU id")
Signed-off-by: Su Hui <[email protected]>
---
drivers/gpu/vga/vga_switcheroo.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 365e6ddbe90f..d3064466fd3a 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -375,7 +375,7 @@ int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
mutex_lock(&vgasr_mutex);
if (vgasr_priv.active) {
id = vgasr_priv.handler->get_client_id(vga_dev);
- if (id < 0) {
+ if ((int)id < 0) {
mutex_unlock(&vgasr_mutex);
return -EINVAL;
}
--
2.30.2
On Thu, Oct 26, 2023 at 10:10:57AM +0800, Su Hui wrote:
> 'id' is enum type like unsigned int, so it will never be less than zero.
>
> Fixes: 4aaf448fa975 ("vga_switcheroo: set audio client id according to bound GPU id")
> Signed-off-by: Su Hui <[email protected]>
> ---
> drivers/gpu/vga/vga_switcheroo.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
> index 365e6ddbe90f..d3064466fd3a 100644
> --- a/drivers/gpu/vga/vga_switcheroo.c
> +++ b/drivers/gpu/vga/vga_switcheroo.c
> @@ -375,7 +375,7 @@ int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
> mutex_lock(&vgasr_mutex);
> if (vgasr_priv.active) {
> id = vgasr_priv.handler->get_client_id(vga_dev);
> - if (id < 0) {
> + if ((int)id < 0) {
Hi,
I feel like you're using Smatch? Which is great! Fantastic!
Have you built the cross function database? If you have there is a
command that's useful.
$ ~/smatch/smatch_db/smdb.py functions vga_switcheroo_handler get_client_id | tee where
drivers/gpu/drm/nouveau/nouveau_acpi.c | (struct vga_switcheroo_handler)->get_client_id | nouveau_dsm_get_client_id | 1
drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c | (struct vga_switcheroo_handler)->get_client_id | amdgpu_atpx_get_client_id | 1
drivers/gpu/drm/radeon/radeon_atpx_handler.c | (struct vga_switcheroo_handler)->get_client_id | radeon_atpx_get_client_id | 1
drivers/platform/x86/apple-gmux.c | (struct vga_switcheroo_handler)->get_client_id | gmux_get_client_id | 1
$ make cscope
$ vim where
Use cscope to jump to each of those four functions. Move the cursor to
the nouveau_dsm_get_client_id and hit CTRL-].
They never return negatives. The enum vga_switcheroo_client_id has a
VGA_SWITCHEROO_UNKNOWN_ID define which I guess these functions are
supposed to return on error. They never do return that, but I bet
that's what we are supposed to check for. It honestly might be good
to check for both...
if ((int)id < 0 || id == VGA_SWITCHEROO_UNKNOWN_ID) {
mutex_unlock(&vgasr_mutex);
return -EINVAL;
}
regards,
dan carpenter
On 2023/10/26 12:44, Dan Carpenter wrote:
> On Thu, Oct 26, 2023 at 10:10:57AM +0800, Su Hui wrote:
>> 'id' is enum type like unsigned int, so it will never be less than zero.
>>
>> Fixes: 4aaf448fa975 ("vga_switcheroo: set audio client id according to bound GPU id")
>> Signed-off-by: Su Hui <[email protected]>
>> ---
>> drivers/gpu/vga/vga_switcheroo.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
>> index 365e6ddbe90f..d3064466fd3a 100644
>> --- a/drivers/gpu/vga/vga_switcheroo.c
>> +++ b/drivers/gpu/vga/vga_switcheroo.c
>> @@ -375,7 +375,7 @@ int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
>> mutex_lock(&vgasr_mutex);
>> if (vgasr_priv.active) {
>> id = vgasr_priv.handler->get_client_id(vga_dev);
>> - if (id < 0) {
>> + if ((int)id < 0) {
> Hi,
>
> I feel like you're using Smatch? Which is great! Fantastic!
Yep, Smatch helps me a lot to find these bugs! I really like this
excellent tool!
>
> Have you built the cross function database? If you have there is a
> command that's useful.
Not yet, bu I want to build this.
> $ ~/smatch/smatch_db/smdb.py functions vga_switcheroo_handler get_client_id | tee where
> drivers/gpu/drm/nouveau/nouveau_acpi.c | (struct vga_switcheroo_handler)->get_client_id | nouveau_dsm_get_client_id | 1
> drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c | (struct vga_switcheroo_handler)->get_client_id | amdgpu_atpx_get_client_id | 1
> drivers/gpu/drm/radeon/radeon_atpx_handler.c | (struct vga_switcheroo_handler)->get_client_id | radeon_atpx_get_client_id | 1
> drivers/platform/x86/apple-gmux.c | (struct vga_switcheroo_handler)->get_client_id | gmux_get_client_id | 1
> $ make cscope
> $ vim where
> Use cscope to jump to each of those four functions. Move the cursor to
> the nouveau_dsm_get_client_id and hit CTRL-].
Sounds great! I must try this!
>
> They never return negatives. The enum vga_switcheroo_client_id has a
> VGA_SWITCHEROO_UNKNOWN_ID define which I guess these functions are
> supposed to return on error. They never do return that, but I bet
> that's what we are supposed to check for. It honestly might be good
> to check for both...
>
> if ((int)id < 0 || id == VGA_SWITCHEROO_UNKNOWN_ID) {
> mutex_unlock(&vgasr_mutex);
> return -EINVAL;
> }
Agreed, I will send v2 patch soon.
Really thanks for your wonderful suggestion! :)
Su Hui
> regards,
> dan carpenter
>
On Thu, Oct 26, 2023 at 04:46:29PM +0800, Su Hui wrote:
> On 2023/10/26 12:44, Dan Carpenter wrote:
> > On Thu, Oct 26, 2023 at 10:10:57AM +0800, Su Hui wrote:
> > > 'id' is enum type like unsigned int, so it will never be less than zero.
> > >
> > > Fixes: 4aaf448fa975 ("vga_switcheroo: set audio client id according to bound GPU id")
> > > Signed-off-by: Su Hui <[email protected]>
> > > ---
> > > drivers/gpu/vga/vga_switcheroo.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
> > > index 365e6ddbe90f..d3064466fd3a 100644
> > > --- a/drivers/gpu/vga/vga_switcheroo.c
> > > +++ b/drivers/gpu/vga/vga_switcheroo.c
> > > @@ -375,7 +375,7 @@ int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
> > > mutex_lock(&vgasr_mutex);
> > > if (vgasr_priv.active) {
> > > id = vgasr_priv.handler->get_client_id(vga_dev);
> > > - if (id < 0) {
> > > + if ((int)id < 0) {
> > Hi,
> >
> > I feel like you're using Smatch? Which is great! Fantastic!
> Yep, Smatch helps me? a lot to find these bugs! I really like this excellent
> tool!
> >
> > Have you built the cross function database? If you have there is a
> > command that's useful.
> Not yet, bu I want to build this.
Yeah. It's super useful for kernel development. It helps to understand
how functions are called and where variables are set etc. The smatch
documentation is crap, I know. But I did write a short blog about the
cross function DB.
https://staticthinking.wordpress.com/2023/05/02/the-cross-function-db/
It's simple to build, but it takes a long time. Just run
smatch_scripts/build_kernel_data.sh
regards,
dan carpenter