Re: panic: invalid bcd xxx

This is an emulated BIOS though, right?

I don't know if we're going to get the RTC 'bugfixed'...


-adrian

On 28 February 2017 at 15:26, Michael Gmelin <freebsd_at_grem.de> wrote:
> On Tue, 28 Feb 2017 17:16:02 -0600
> Eric van Gyzen <vangyzen_at_FreeBSD.org> wrote:
>
>> On 02/28/2017 16:57, Conrad Meyer wrote:
>> > On Tue, Feb 28, 2017 at 2:31 PM, Eric van Gyzen
>> > <vangyzen_at_freebsd.org> wrote:
>> >> Your system's real-time clock is returning garbage.  r312702 added
>> >> some input validation a few weeks ago.  Previously, the kernel was
>> >> reading beyond the end of an array and either complaining about
>> >> the clock or setting it to the wrong time based on whatever was in
>> >> the memory beyond the array.
>> >>
>> >> The added validation shouldn't be an assertion because it operates
>> >> on data beyond the kernel's control.  Try this:
>> >>
>> >> --- sys/libkern.h       (revision 314424)
>> >> +++ sys/libkern.h       (working copy)
>> >> _at__at_ -57,8 +57,10 _at__at_
>> >>  bcd2bin(int bcd)
>> >>  {
>> >>
>> >> -       KASSERT(bcd >= 0 && bcd < LIBKERN_LEN_BCD2BIN,
>> >> -           ("invalid bcd %d", bcd));
>> >> +       if (bcd < 0 || bcd >= LIBKERN_LEN_BCD2BIN) {
>> >> +               printf("invalid bcd %d\n", bcd);
>> >> +               return (0);
>> >> +       }
>> >>         return (bcd2bin_data[bcd]);
>> >>  }
>> >
>> > I don't think removing this assertion and truncating to zero is the
>> > right thing to do.  Adding an error return to this routine is a
>> > little much, though.  I think probably the caller should perform
>> > input validation between the broken device and this routine.
>>
>> Either of those would be a much better solution.  This was just a
>> quick hack to get the memstick to boot.
>>
>
> Thanks for your response.
>
> I'm not in a hurry, so I can wait for a proper solution. Let me know if
> I should test anything or can help in some other way.
>
> -m
>
>
> --
> Michael Gmelin
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