Re: [Intel-gfx] [PATCH] drm: i915: Adapt to -Walloc-size
Jani Nikula writes:
> On Tue, 07 Nov 2023, Sam James wrote:
>> GCC 14 introduces a new -Walloc-size included in -Wextra which errors out
>> like:
>> ```
>> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c: In function
>> ‘eb_copy_relocations’:
>> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c:1681:24: error: allocation of
>> insufficient size ‘1’ for type ‘struct drm_i915_gem_relocation_entry’ with
>> size ‘32’ [-Werror=alloc-size]
>> 1681 | relocs = kvmalloc_array(size, 1, GFP_KERNEL);
>> |^
>>
>> ```
>>
>> So, just swap the number of members and size arguments to match the
>> prototype, as
>> we're initialising 1 element of size `size`. GCC then sees we're not
>> doing anything wrong.
>>
>> Signed-off-by: Sam James
>
> The short answer,
>
> Reviewed-by: Jani Nikula
>
> but please read on.
>
>> ---
>> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> index 683fd8d3151c..45b9d9e34b8b 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> @@ -1678,7 +1678,7 @@ static int eb_copy_relocations(const struct
>> i915_execbuffer *eb)
>> urelocs = u64_to_user_ptr(eb->exec[i].relocs_ptr);
>> size = nreloc * sizeof(*relocs);
>>
>> -relocs = kvmalloc_array(size, 1, GFP_KERNEL);
>> +relocs = kvmalloc_array(1, size, GFP_KERNEL);
>
> Based on the patch context, we should really be calling:
>
> kvmalloc_array(nreloc, sizeof(*relocs), GFP_KERNEL);
>
> and we'd get mul overflow checks too.
>
> However, the code below also needs size, unless it's refactored to
> operate on multiples of sizeof(*relocs) and it all gets a bit annoying.
>
> Maybe there's a better way, but for the short term the patch at hand is
> no worse than what we currently have, and it'll silence the warning, so
> let's go with this.
Thanks. I have been trying to port to kvmalloc_array where I can if it's
obvious/trivial, but I admit I didn't want to take it on when it'd
require any surrounding refactoring unless someone insisted.
>
>
>> if (!relocs) {
>> err = -ENOMEM;
>> goto err;
best,
sam
Re: [Intel-gfx] [PATCH] drm: i915: Adapt to -Walloc-size
On Wed, 08 Nov 2023, Jani Nikula wrote:
> On Tue, 07 Nov 2023, Sam James wrote:
>> GCC 14 introduces a new -Walloc-size included in -Wextra which errors out
>> like:
>> ```
>> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c: In function
>> ‘eb_copy_relocations’:
>> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c:1681:24: error: allocation of
>> insufficient size ‘1’ for type ‘struct drm_i915_gem_relocation_entry’ with
>> size ‘32’ [-Werror=alloc-size]
>> 1681 | relocs = kvmalloc_array(size, 1, GFP_KERNEL);
>> |^
>>
>> ```
>>
>> So, just swap the number of members and size arguments to match the
>> prototype, as
>> we're initialising 1 element of size `size`. GCC then sees we're not
>> doing anything wrong.
>>
>> Signed-off-by: Sam James
>
> The short answer,
>
> Reviewed-by: Jani Nikula
And pushed to drm-intel-gt-next, thanks for the patch.
BR,
Jani.
>
> but please read on.
>
>> ---
>> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> index 683fd8d3151c..45b9d9e34b8b 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
>> @@ -1678,7 +1678,7 @@ static int eb_copy_relocations(const struct
>> i915_execbuffer *eb)
>> urelocs = u64_to_user_ptr(eb->exec[i].relocs_ptr);
>> size = nreloc * sizeof(*relocs);
>>
>> -relocs = kvmalloc_array(size, 1, GFP_KERNEL);
>> +relocs = kvmalloc_array(1, size, GFP_KERNEL);
>
> Based on the patch context, we should really be calling:
>
> kvmalloc_array(nreloc, sizeof(*relocs), GFP_KERNEL);
>
> and we'd get mul overflow checks too.
>
> However, the code below also needs size, unless it's refactored to
> operate on multiples of sizeof(*relocs) and it all gets a bit annoying.
>
> Maybe there's a better way, but for the short term the patch at hand is
> no worse than what we currently have, and it'll silence the warning, so
> let's go with this.
>
>
>> if (!relocs) {
>> err = -ENOMEM;
>> goto err;
--
Jani Nikula, Intel
[Intel-gfx] [PATCH] drm: i915: Adapt to -Walloc-size
GCC 14 introduces a new -Walloc-size included in -Wextra which errors out
like:
```
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c: In function
‘eb_copy_relocations’:
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c:1681:24: error: allocation of
insufficient size ‘1’ for type ‘struct drm_i915_gem_relocation_entry’ with size
‘32’ [-Werror=alloc-size]
1681 | relocs = kvmalloc_array(size, 1, GFP_KERNEL);
|^
```
So, just swap the number of members and size arguments to match the prototype,
as
we're initialising 1 element of size `size`. GCC then sees we're not
doing anything wrong.
Signed-off-by: Sam James
---
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 683fd8d3151c..45b9d9e34b8b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -1678,7 +1678,7 @@ static int eb_copy_relocations(const struct
i915_execbuffer *eb)
urelocs = u64_to_user_ptr(eb->exec[i].relocs_ptr);
size = nreloc * sizeof(*relocs);
- relocs = kvmalloc_array(size, 1, GFP_KERNEL);
+ relocs = kvmalloc_array(1, size, GFP_KERNEL);
if (!relocs) {
err = -ENOMEM;
goto err;
--
2.42.1
Re: [Intel-gfx] [PATCH] drm: i915: Adapt to -Walloc-size
On Tue, 07 Nov 2023, Sam James wrote:
> GCC 14 introduces a new -Walloc-size included in -Wextra which errors out
> like:
> ```
> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c: In function
> ‘eb_copy_relocations’:
> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c:1681:24: error: allocation of
> insufficient size ‘1’ for type ‘struct drm_i915_gem_relocation_entry’ with
> size ‘32’ [-Werror=alloc-size]
> 1681 | relocs = kvmalloc_array(size, 1, GFP_KERNEL);
> |^
>
> ```
>
> So, just swap the number of members and size arguments to match the
> prototype, as
> we're initialising 1 element of size `size`. GCC then sees we're not
> doing anything wrong.
>
> Signed-off-by: Sam James
The short answer,
Reviewed-by: Jani Nikula
but please read on.
> ---
> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index 683fd8d3151c..45b9d9e34b8b 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -1678,7 +1678,7 @@ static int eb_copy_relocations(const struct
> i915_execbuffer *eb)
> urelocs = u64_to_user_ptr(eb->exec[i].relocs_ptr);
> size = nreloc * sizeof(*relocs);
>
> - relocs = kvmalloc_array(size, 1, GFP_KERNEL);
> + relocs = kvmalloc_array(1, size, GFP_KERNEL);
Based on the patch context, we should really be calling:
kvmalloc_array(nreloc, sizeof(*relocs), GFP_KERNEL);
and we'd get mul overflow checks too.
However, the code below also needs size, unless it's refactored to
operate on multiples of sizeof(*relocs) and it all gets a bit annoying.
Maybe there's a better way, but for the short term the patch at hand is
no worse than what we currently have, and it'll silence the warning, so
let's go with this.
> if (!relocs) {
> err = -ENOMEM;
> goto err;
--
Jani Nikula, Intel
