1430 	struct frame_tail buftail;  in user_backtrace()  local
1434 	if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))  in user_backtrace()
1438 	err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));  in user_backtrace()
1444 	perf_callchain_store(entry, buftail.lr);  in user_backtrace()
1450 	if (tail >= buftail.fp)  in user_backtrace()
1453 	return buftail.fp;  in user_backtrace()
1475 	struct compat_frame_tail buftail;  in compat_user_backtrace()  local
1479 	if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))  in compat_user_backtrace()
1483 	err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));  in compat_user_backtrace()
1489 	perf_callchain_store(entry, buftail.lr);  in compat_user_backtrace()
1496 			compat_ptr(buftail.fp))  in compat_user_backtrace()
1499 	return (struct compat_frame_tail __user *)compat_ptr(buftail.fp) - 1;  in compat_user_backtrace()