tee: optee: Fix incorrect page free bug

Pointer to the allocated pages (struct page *page) has already
progressed towards the end of allocation. It is incorrect to perform
__free_pages(page, order) using this pointer as we would free any
arbitrary pages. Fix this by stop modifying the page pointer.

Fixes: ec185dd ("optee: Fix memory leak when failing to register shm pages")
Cc: stable@vger.kernel.org
Reported-by: Patrik Lantz <patrik.lantz@axis.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

drivers/tee/optee/core.c

@@ -48,10 +48,8 @@ int optee_pool_op_alloc_helper(struct tee_shm_pool_mgr *poolm,
 			goto err;
 		}
 
-		for (i = 0; i < nr_pages; i++) {
-			pages[i] = page;
-			page++;
-		}
+		for (i = 0; i < nr_pages; i++)
+			pages[i] = page + i;
 
 		shm->flags |= TEE_SHM_REGISTER;
 		rc = shm_register(shm->ctx, shm, pages, nr_pages,