On Thu, Jan 5, 2023, at 06:54, kernel test robot wrote:
> Greeting,
>
> FYI, we noticed BUG:kernel_NULL_pointer_dereference,address due to
> commit (built with clang-14):
>
> commit: aa0652d7f1b311e55232a8153522fdaaba0f197a ("tty: serial: handle
> HAS_IOPORT dependencies")
> https://git.kernel.org/cgit/linux/kernel/git/niks/linux.git
> has_ioport_v3
>
> in testcase: boot
>
> on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G
>
> caused below changes (please refer to attached dmesg/kmsg for entire
> log/backtrace):
>
>
> [ 2.166733][ T0] calling univ8250_console_init+0x0/0x30 @ 0
> [ 2.167555][ T0] BUG: kernel NULL pointer dereference, address:
> 00000000
I think it's this bit:
@@ -508,12 +523,13 @@ static void set_io_from_upio(struct uart_port *p)
up->dl_read = au_serial_dl_read;
up->dl_write = au_serial_dl_write;
break;
-#endif
-
+#ifdef CONFIG_HAS_IOPORT
default:
p->serial_in = io_serial_in;
p->serial_out = io_serial_out;
break;
+#endif
+#endif
}
/* Remember loaded iotype */
up->cur_iotype = p->iotype;
which puts the 'default' case inside of '#ifdef
CONFIG_SERIAL_8250_RT288X'. x86 does not use the
RT288x variant but relies on the default, so any
call to io_serial_{in,out} will cause a NULL
pointer dereference.
Arnd
