[PATCH v1] drm/amdgpu: fix byte/dword unit mismatch in coredump IB dump

[PATCH v1] drm/amdgpu: fix byte/dword unit mismatch in coredump IB dump

[Sunil Khatri]

In amdgpu_devcoredump_print_ibs(), the NO_CPU_ACCESS VRAM path passed
cursor.start/4 and cursor.size/4 to amdgpu_device_mm_access(), but that
function's pos/size parameters are byte offsets/lengths (confirmed by
amdgpu_ttm_vram_mm_access() and leading to wrong size calculation.

Similarly with that change the off index needs to be calculated
based on dword since that is a u32 type.

Fixes: 7b15fc2d1f1a ("drm/amdgpu: dump job ibs in the devcoredump")
Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c
index 76771ad30c41..2d3fb87af00a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c
@@ -297,10 +297,10 @@ amdgpu_devcoredump_print_ibs(struct drm_printer *p,
 			amdgpu_res_first(abo->tbo.resource, offset,
 					 coredump->ibs[i].ib_size_dw * 4, &cursor);
 			while (cursor.remaining) {
-				amdgpu_device_mm_access(adev, cursor.start / 4,
-							&ib_content[off], cursor.size / 4,
+				amdgpu_device_mm_access(adev, cursor.start,
+							&ib_content[off], cursor.size,
 							false);
-				off += cursor.size;
+				off += cursor.size / 4;
 				amdgpu_res_next(&cursor, cursor.size);
 			}
 			emit_content = true;
-- 
2.34.1

Re: [PATCH v1] drm/amdgpu: fix byte/dword unit mismatch in coredump IB dump

[Khatri, Sunil]

+ pierre-eric

On 27-08-2026 10:07 pm, Sunil Khatri wrote:
> In amdgpu_devcoredump_print_ibs(), the NO_CPU_ACCESS VRAM path passed
> cursor.start/4 and cursor.size/4 to amdgpu_device_mm_access(), but that
> function's pos/size parameters are byte offsets/lengths (confirmed by
> amdgpu_ttm_vram_mm_access() and leading to wrong size calculation.
>
> Similarly with that change the off index needs to be calculated
> based on dword since that is a u32 type.
>
> Fixes: 7b15fc2d1f1a ("drm/amdgpu: dump job ibs in the devcoredump")
> Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c
> index 76771ad30c41..2d3fb87af00a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c
> @@ -297,10 +297,10 @@ amdgpu_devcoredump_print_ibs(struct drm_printer *p,
>   			amdgpu_res_first(abo->tbo.resource, offset,
>   					 coredump->ibs[i].ib_size_dw * 4, &cursor);
>   			while (cursor.remaining) {
> -				amdgpu_device_mm_access(adev, cursor.start / 4,
> -							&ib_content[off], cursor.size / 4,
> +				amdgpu_device_mm_access(adev, cursor.start,
> +							&ib_content[off], cursor.size,
>   							false);
> -				off += cursor.size;
> +				off += cursor.size / 4;
>   				amdgpu_res_next(&cursor, cursor.size);
>   			}
>   			emit_content = true;