On 05/04/2015 01:45 PM, Jan Kiszka wrote: > On 2015-05-04 19:02, Peter Hurley wrote: >> Hi Jan, >> >> On 05/04/2015 12:01 PM, Jan Kiszka wrote: >>> When nr_uarts was set to 0 (via config or 8250_core.nr_uarts), we crash >>> early on x86 because serial8250_isa_init_ports dereferences base_ops >>> which remains NULL. In fact, there is nothing to do for that function if >>> there are no uarts. >> >> Thanks for finding this. >> >> So nr_uarts == 0 effectively disables the 8250 driver. Is there any >> reason not to simply abort the driver init instead? > > I'm not very deep into this code, just stumbled over this while trying > some, well, unusual configurations. Ok; I wasn't sure if this was related to some weird setup that needed the 8250 driver loaded but in-op. > If you prefer to handle this differently, I can recode it, of course. Yes, please. We should bail out of any initialization if nr_uarts == 0. That would be: 1. univ8250_console_init() The return value is ignored but the console should not be registered. 2. early_serial_setup() if (nr_uarts == 0) return -ENODEV; 3. serial8250_init() if (nr_uarts == 0) return -ENODEV; Regards, Peter Hurley -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
