[PATCH v4 1/3] drm/panthor: Check for sparse binding range overflow

["Adrián Larumbe" <adrian.larumbe@collabora.com>]

This check is being already carried out further down the call stack inside
drm_gpuvm_sm_map -> drm_gpuvm_range_valid, but it's best to fail early in
the driver before GPUVM functions are invoked so that we won't waste time
allocating vm_bind context resources.

Reported-by: Sashiko <noreply@sashiko.dev>
Closes: https://sashiko.dev/#/message/20260623204220.CDB1B1F000E9%40smtp.kernel.org
Fixes: 12cf826bf1dd ("drm/panthor: Support sparse mappings")
Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
---
 drivers/gpu/drm/panthor/panthor_mmu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index 31cc57029c12..163231c1703d 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -2975,12 +2975,16 @@ panthor_vm_bind_prepare_op_ctx(struct drm_file *file,
 {
 	ssize_t vm_pgsz = panthor_vm_page_size(vm);
 	struct drm_gem_object *gem;
+	u64 end;
 	int ret;
 
 	/* Aligned on page size. */
 	if (!IS_ALIGNED(op->va | op->size | op->bo_offset, vm_pgsz))
 		return -EINVAL;
 
+	if (check_add_overflow(op->va, op->size, &end))
+		return -EINVAL;
+
 	switch (op->flags & DRM_PANTHOR_VM_BIND_OP_TYPE_MASK) {
 	case DRM_PANTHOR_VM_BIND_OP_TYPE_MAP:
 		if (!(op->flags & DRM_PANTHOR_VM_BIND_OP_MAP_SPARSE)) {

-- 
2.55.0