svn commit: r238907 - projects/calloutng/sys/kern

[Attilio Rao]

On Mon, Jul 30, 2012 at 4:31 PM, Andriy Gapon <avg at freebsd.org> wrote:
> on 30/07/2012 18:04 Attilio Rao said the following:
>> On 7/30/12, Andriy Gapon <avg at freebsd.org> wrote:
>>> on 30/07/2012 17:56 Attilio Rao said the following:
>>>> More explicitly, I think such combination TDP_NOSLEEPING +
>>>> TDP_NOBLOCKING (name invented) should be set on entering the interrupt
>>>> context, not only related to this part of callouts. This would be a
>>>> very good help for catching buggy situations.
>>>
>>> Something very tangential.  I think it would also be nice to check if a
>>> thread has
>>> any(?) locks held when returning to userland.
>>
>> This happens already for INVARIANTS case, with td_locks counters.
>> In the !INVARIANTS case, this doesn't happen because you don't want to
>> add the burden to bump td_locks for the fast case and I think it is a
>> good approach.
>
> Ah, I missed that, thank you.
> BTW, it seems that td_locks is checked twice in normal syscallret() path: once in
> syscallret() itself and then in userret().  On this note, would it make sense to
> move the whole nine yards of asserts from syscallret() to userret()?
> I mean it might make sense to have those checks (td_critnest, td_pflags) in other
> paths to userland.

Nice catch.
The checks were added to syscallret() in r208453. While this is fine,
I think that putting them in userret() may give them more exposure and
cover also cases like traps which are not covered right now.
If you want to make a patch that moves these conditions in userret()
I'd be in favor of it.

Thanks,
Attilio


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