Re: Mainline kernel crashes, was Re: RFC: remove set_fs for m68k

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Finn,

On 13/09/21 19:20, Michael Schmitz wrote:
>>>
>>> Incidentally - have you ever checked whether Al Viro's signal handling
>>> fixes have an impact on these bugs?
>>>
>>
>> I will try that patch series if you think it is related.
>
> Initial tests look promising (but I've said that before).
>
>> So far the problem seems to be confined to one machine. Stress tests on
>> other mac models did not yet reproduce the problem.
>
> Yes, that's suspicious. I'll keep you posted.

I've seen neither format errors in resume_userspace() nor bus errors in 
setup_frame() after two days of tests (and would have expected multiple 
errors in that amount of time). Al's patches appear to have fixed these 
errors for me. And that makes a lot of sense, considering handling of 
multiple signals was broken before, and would have been expected to 
result in corrupt exception frames on return from exception, and just 
the sort of format errors I'd seen.

I still have to trace what issues the incorrect exception stack handling 
would have caused in setup_frame() to force a bus error on the first 
__put_user() there.

My tests were run successfully without any disabling of interrupts games 
BTW.

The issues on 040 would be very similar, and I don't think you'd seen 
format errors on exception return or bus errors in setup_frame(), so 
this might not matter to you.

Cheers,

	Michael