Re: panic: invalid bcd xxx

From: Michael Gmelin <freebsd_at_grem.de>
Date: Thu, 2 Mar 2017 00:37:35 +0100
> On 2 Mar 2017, at 00:35, Adrian Chadd <adrian.chadd_at_gmail.com> wrote:
> 
> This is an emulated BIOS though, right?
> 
> I don't know if we're going to get the RTC 'bugfixed'...
> 


It's SeaBIOS, yes. I feel like this might end up in another quirk/workaround solution.

-m


> 
> -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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Received on Wed Mar 01 2017 - 22:37:45 UTC

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