Re: page fault in pfioctl

On 25/09/2021 19:34, Kristof Provost wrote:
> On 25 Sep 2021, at 18:25, Andriy Gapon wrote:
>> On 13/06/2021 11:19, Kristof Provost wrote:
>>> On 13 Jun 2021, at 09:41, Andriy Gapon <avg@freebsd.org> wrote:
>>>> Based on
>>>> the panic message (page fault with non-sleepable locks held), it seems that
>>>> the problem is with holding the lock across the copyout.  Usually that
>>>> won't panic, but if the destination happens to be paged out... And only
>>>> with INVARIANTS, I guess...
>>>
>>> Oh right. Thanks. I’ve gotten bitten by that one before, but had clearly
>>> garbage collected the memory.
>>>
>>> I’ll fix this one and check for others on Monday.
>>>
>>> I’ll also see of we can persuade copyout to always panic on this bug, not
>>> just when the destination memory is actually paged out. That way we’ll catch
>>> this in the regression tests in the future.
>>
>> I upgraded to the latest stable/13 and hit a fresh panic of the same type.
>> This time it's in pf_getstatus() and it's a copyout while 'pf rulesets' lock is held.
>>
> I believe that’s fixed by https://cgit.freebsd.org/src/commit/sys/netpfil/pf/pf_ioctl.c?id=cb13059663e455b3fc69c293dadec53c164490dc

Thank you for the pointer!
I believe it should help with the witness warning.
Still not sure what's going on with copyout_nosmap_std().

-- 
Andriy Gapon