habanalabs: check correct vmalloc return code

vmalloc can return different return code than NULL and a valid
pointer. We must validate it in order to dereference a non valid
pointer.
Signed-off-by: NOfir Bitton <obitton@habana.ai>
Signed-off-by: NOded Gabbay <oded.gabbay@gmail.com>

drivers/misc/habanalabs/common/memory.c

@@ -66,6 +66,11 @@ static int alloc_device_memory(struct hl_ctx *ctx, struct hl_mem_in *args,
 	num_pgs = (args->alloc.mem_size + (page_size - 1)) >> page_shift;
 	total_size = num_pgs << page_shift;
 
+	if (!total_size) {
+		dev_err(hdev->dev, "Cannot allocate 0 bytes\n");
+		return -EINVAL;
+	}
+
 	contiguous = args->flags & HL_MEM_CONTIGUOUS;
 
 	if (contiguous) {
@@ -93,7 +98,7 @@ static int alloc_device_memory(struct hl_ctx *ctx, struct hl_mem_in *args,
 	phys_pg_pack->contiguous = contiguous;
 
 	phys_pg_pack->pages = kvmalloc_array(num_pgs, sizeof(u64), GFP_KERNEL);
-	if (!phys_pg_pack->pages) {
+	if (ZERO_OR_NULL_PTR(phys_pg_pack->pages)) {
 		rc = -ENOMEM;
 		goto pages_arr_err;
 	}
@@ -683,7 +688,7 @@ static int init_phys_pg_pack_from_userptr(struct hl_ctx *ctx,
 
 	phys_pg_pack->pages = kvmalloc_array(total_npages, sizeof(u64),
 						GFP_KERNEL);
-	if (!phys_pg_pack->pages) {
+	if (ZERO_OR_NULL_PTR(phys_pg_pack->pages)) {
 		rc = -ENOMEM;
 		goto page_pack_arr_mem_err;
 	}

drivers/misc/habanalabs/common/mmu.c

@@ -450,7 +450,7 @@ int hl_mmu_init(struct hl_device *hdev)
 	hdev->mmu_shadow_hop0 = kvmalloc_array(prop->max_asid,
 					prop->mmu_hop_table_size,
 					GFP_KERNEL | __GFP_ZERO);
-	if (!hdev->mmu_shadow_hop0) {
+	if (ZERO_OR_NULL_PTR(hdev->mmu_shadow_hop0)) {
 		rc = -ENOMEM;
 		goto err_pool_add;
 	}