Hello Darwin Dingel,
This is a semi-automatic email about new static checker warnings.
The patch 6d7f677a2afa: "serial: 8250: Rate limit serial port rx
interrupts during input overruns" from Dec 10, 2018, leads to the
following Smatch complaint:
drivers/tty/serial/8250/8250_core.c:1077 serial8250_register_8250_port()
error: we previously assumed 'uart' could be null (see line 984)
drivers/tty/serial/8250/8250_core.c
983 uart = serial8250_find_match_or_unused(&up->port);
984 if (uart && uart->port.type != PORT_8250_CIR) {
^^^^
The old code checked for NULL.
985 if (uart->port.dev)
986 uart_remove_one_port(&serial8250_reg, &uart->port);
987
988 uart->port.iobase = up->port.iobase;
989 uart->port.membase = up->port.membase;
990 uart->port.irq = up->port.irq;
991 uart->port.irqflags = up->port.irqflags;
992 uart->port.uartclk = up->port.uartclk;
993 uart->port.fifosize = up->port.fifosize;
994 uart->port.regshift = up->port.regshift;
995 uart->port.iotype = up->port.iotype;
996 uart->port.flags = up->port.flags | UPF_BOOT_AUTOCONF;
997 uart->bugs = up->bugs;
998 uart->port.mapbase = up->port.mapbase;
999 uart->port.mapsize = up->port.mapsize;
1000 uart->port.private_data = up->port.private_data;
1001 uart->tx_loadsz = up->tx_loadsz;
1002 uart->capabilities = up->capabilities;
1003 uart->port.throttle = up->port.throttle;
1004 uart->port.unthrottle = up->port.unthrottle;
1005 uart->port.rs485_config = up->port.rs485_config;
1006 uart->port.rs485 = up->port.rs485;
1007 uart->dma = up->dma;
1008
1009 /* Take tx_loadsz from fifosize if it wasn't set separately */
1010 if (uart->port.fifosize && !uart->tx_loadsz)
1011 uart->tx_loadsz = uart->port.fifosize;
1012
1013 if (up->port.dev)
1014 uart->port.dev = up->port.dev;
1015
1016 if (up->port.flags & UPF_FIXED_TYPE)
1017 uart->port.type = up->port.type;
1018
1019 serial8250_set_defaults(uart);
1020
1021 /* Possibly override default I/O functions. */
1022 if (up->port.serial_in)
1023 uart->port.serial_in = up->port.serial_in;
1024 if (up->port.serial_out)
1025 uart->port.serial_out = up->port.serial_out;
1026 if (up->port.handle_irq)
1027 uart->port.handle_irq = up->port.handle_irq;
1028 /* Possibly override set_termios call */
1029 if (up->port.set_termios)
1030 uart->port.set_termios = up->port.set_termios;
1031 if (up->port.set_ldisc)
1032 uart->port.set_ldisc = up->port.set_ldisc;
1033 if (up->port.get_mctrl)
1034 uart->port.get_mctrl = up->port.get_mctrl;
1035 if (up->port.set_mctrl)
1036 uart->port.set_mctrl = up->port.set_mctrl;
1037 if (up->port.get_divisor)
1038 uart->port.get_divisor = up->port.get_divisor;
1039 if (up->port.set_divisor)
1040 uart->port.set_divisor = up->port.set_divisor;
1041 if (up->port.startup)
1042 uart->port.startup = up->port.startup;
1043 if (up->port.shutdown)
1044 uart->port.shutdown = up->port.shutdown;
1045 if (up->port.pm)
1046 uart->port.pm = up->port.pm;
1047 if (up->port.handle_break)
1048 uart->port.handle_break = up->port.handle_break;
1049 if (up->dl_read)
1050 uart->dl_read = up->dl_read;
1051 if (up->dl_write)
1052 uart->dl_write = up->dl_write;
1053
1054 if (uart->port.type != PORT_8250_CIR) {
1055 if (serial8250_isa_config != NULL)
1056 serial8250_isa_config(0, &uart->port,
1057 &uart->capabilities);
1058
1059 serial8250_apply_quirks(uart);
1060 ret = uart_add_one_port(&serial8250_reg,
1061 &uart->port);
1062 if (ret == 0)
1063 ret = uart->port.line;
1064 } else {
1065 dev_info(uart->port.dev,
1066 "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
1067 uart->port.iobase,
1068 (unsigned long long)uart->port.mapbase,
1069 uart->port.irq);
1070
1071 ret = 0;
1072 }
1073 }
1074
1075 /* Initialise interrupt backoff work if required */
1076 if (up->overrun_backoff_time_ms > 0) {
1077 uart->overrun_backoff_time_ms = up->overrun_backoff_time_ms;
^^^^
1078 INIT_DELAYED_WORK(&uart->overrun_backoff,
1079 serial_8250_overrun_backoff_work);
1080 } else {
1081 uart->overrun_backoff_time_ms = 0;
^^^^^^
The patch adds unchecked dereferences.
1082 }
1083
1084 mutex_unlock(&serial_mutex);
1085
1086 return ret;
1087 }
regards,
dan carpenter
