accel/amdxdna: Remove __counted_by from struct amdxdna_cmd_chain

[PATCH V1] accel/amdxdna: Remove __counted_by from struct amdxdna_cmd_chain

Posted by Lizhi Hou 1 month, 1 week ago

struct amdxdna_cmd_chain contains a flexible array annotated with
__counted_by(command_count). Since the structure is stored in shared
AMDXDNA_BO_SHARE memory, userspace can modify command_count concurrently.
If command_count is changed to zero, the bounds check generated from
__counted_by may fail and trigger a kernel panic.

Remove __counted_by to avoid relying on the userspace-controlled
command_count for the flexible array bounds check.

Fixes: aac243092b70 ("accel/amdxdna: Add command execution")
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
---
 drivers/accel/amdxdna/amdxdna_ctx.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/accel/amdxdna/amdxdna_ctx.h b/drivers/accel/amdxdna/amdxdna_ctx.h
index e6155f4b5db0..010538cb05a3 100644
--- a/drivers/accel/amdxdna/amdxdna_ctx.h
+++ b/drivers/accel/amdxdna/amdxdna_ctx.h
@@ -56,7 +56,7 @@ struct amdxdna_cmd_chain {
 	u32 submit_index;
 	u32 error_index;
 	u32 reserved[3];
-	u64 data[] __counted_by(command_count);
+	u64 data[];
 };
 
 /*
-- 
2.34.1

Re: [PATCH V1] accel/amdxdna: Remove __counted_by from struct amdxdna_cmd_chain

Posted by Max Zhen 1 month, 1 week ago


On 8/20/2026 Thu 20:35, Lizhi Hou wrote:
> struct amdxdna_cmd_chain contains a flexible array annotated with
> __counted_by(command_count). Since the structure is stored in shared
> AMDXDNA_BO_SHARE memory, userspace can modify command_count concurrently.
> If command_count is changed to zero, the bounds check generated from
> __counted_by may fail and trigger a kernel panic.
> 
> Remove __counted_by to avoid relying on the userspace-controlled
> command_count for the flexible array bounds check.
> 
> Fixes: aac243092b70 ("accel/amdxdna: Add command execution")
> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Reviewed-by: Max Zhen <max.zhen@amd.com>
> ---
>   drivers/accel/amdxdna/amdxdna_ctx.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/accel/amdxdna/amdxdna_ctx.h b/drivers/accel/amdxdna/amdxdna_ctx.h
> index e6155f4b5db0..010538cb05a3 100644
> --- a/drivers/accel/amdxdna/amdxdna_ctx.h
> +++ b/drivers/accel/amdxdna/amdxdna_ctx.h
> @@ -56,7 +56,7 @@ struct amdxdna_cmd_chain {
>   	u32 submit_index;
>   	u32 error_index;
>   	u32 reserved[3];
> -	u64 data[] __counted_by(command_count);
> +	u64 data[];
>   };
>   
>   /*

Re: [PATCH V1] accel/amdxdna: Remove __counted_by from struct amdxdna_cmd_chain

Posted by Lizhi Hou 1 month ago

Applied to drm-misc-fixes.

On 8/21/26 10:50, Max Zhen wrote:
>
>
> On 8/20/2026 Thu 20:35, Lizhi Hou wrote:
>> struct amdxdna_cmd_chain contains a flexible array annotated with
>> __counted_by(command_count). Since the structure is stored in shared
>> AMDXDNA_BO_SHARE memory, userspace can modify command_count 
>> concurrently.
>> If command_count is changed to zero, the bounds check generated from
>> __counted_by may fail and trigger a kernel panic.
>>
>> Remove __counted_by to avoid relying on the userspace-controlled
>> command_count for the flexible array bounds check.
>>
>> Fixes: aac243092b70 ("accel/amdxdna: Add command execution")
>> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
> Reviewed-by: Max Zhen <max.zhen@amd.com>
>> ---
>>   drivers/accel/amdxdna/amdxdna_ctx.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/accel/amdxdna/amdxdna_ctx.h 
>> b/drivers/accel/amdxdna/amdxdna_ctx.h
>> index e6155f4b5db0..010538cb05a3 100644
>> --- a/drivers/accel/amdxdna/amdxdna_ctx.h
>> +++ b/drivers/accel/amdxdna/amdxdna_ctx.h
>> @@ -56,7 +56,7 @@ struct amdxdna_cmd_chain {
>>       u32 submit_index;
>>       u32 error_index;
>>       u32 reserved[3];
>> -    u64 data[] __counted_by(command_count);
>> +    u64 data[];
>>   };
>>     /*
>