Re: [PATCH-next] Fix unintentional integer overflow

From: Christian König
Date: Mon Oct 07 2024 - 09:57:16 EST


Am 05.10.24 um 09:05 schrieb Advait Dhamorikar:
Hi Sathish,

Please collate the changes together with Lijo's suggestion as well,
"1ULL <<" instead of typecast, there are 3 occurrences of the error in
f0b19b84d391.
I could only observe two instances of this error in f0b19b84d391 at:
'mask = (1 << (adev->jpeg.num_jpeg_inst * adev->jpeg.num_jpeg_rings)) - 1;`
and `mask |= 1 << ((i * adev->jpeg.num_jpeg_rings) + j);`

There are a few instances where we can use 1U instead of int as
harvest_config uses unsigned int
(adev->jpeg.harvest_config & (1 << i)
However I think they should be fixed in a separate patch?

No, all of this are numerical problems where not taken into account the size of the destination type.

Saying that all of that are basically just style cleanups which doesn't need to be back-ported in any way, so please drop the Fixes: tag.

And you should probably change the subject line to something like "drm/amdgpu: cleanup shift coding style".

Regards,
Christian.


Thanks and regards,
Advait

On Sat, 5 Oct 2024 at 09:05, Sundararaju, Sathishkumar <sasundar@xxxxxxx> wrote:


On 10/4/2024 11:30 PM, Alex Deucher wrote:
On Fri, Oct 4, 2024 at 5:15 AM Sundararaju, Sathishkumar
<sasundar@xxxxxxx> wrote:
All occurrences of this error fix should have been together in a single patch both in _get and _set callbacks corresponding to f0b19b84d391, please avoid separate patch for each occurrence.

Sorry Alex, I missed to note this yesterday.
I've dropped the patch. Please pick it up once it's fixed up appropriately.
Thanks Alex.

Hi Advait,
Please collate the changes together with Lijo's suggestion as well,
"1ULL <<" instead of typecast, there are 3 occurrences of the error in
f0b19b84d391.

Regards,
Sathish
Thanks,

Alex

Regards,
Sathish


On 10/4/2024 1:46 PM, Advait Dhamorikar wrote:

Fix shift-count-overflow when creating mask.
The expression's value may not be what the
programmer intended, because the expression is
evaluated using a narrower integer type.

Fixes: f0b19b84d391 ("drm/amdgpu: add amdgpu_jpeg_sched_mask debugfs")
Signed-off-by: Advait Dhamorikar <advaitdhamorikar@xxxxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
index 95e2796919fc..7df402c45f40 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
@@ -388,7 +388,7 @@ static int amdgpu_debugfs_jpeg_sched_mask_get(void *data, u64 *val)
for (j = 0; j < adev->jpeg.num_jpeg_rings; ++j) {
ring = &adev->jpeg.inst[i].ring_dec[j];
if (ring->sched.ready)
- mask |= 1 << ((i * adev->jpeg.num_jpeg_rings) + j);
+ mask |= (u64)1 << ((i * adev->jpeg.num_jpeg_rings) + j);
}
}
*val = mask;