Re: elog(DEBUG2 in SpinLocked section. - Mailing list pgsql-hackers

From Andres Freund
Subject Re: elog(DEBUG2 in SpinLocked section.
Date
Msg-id 20200617002736.3m6k5dh3eetwrmup@alap3.anarazel.de
Whole thread Raw
In response to Re: elog(DEBUG2 in SpinLocked section.  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Hi,

On 2020-06-16 19:46:29 -0400, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > I experimented with making the compiler warn about about some of these
> > kinds of mistakes without needing full test coverage:
>
> > I was able to get clang to warn about things like using palloc in signal
> > handlers, or using palloc while holding a spinlock. Which would be
> > great, except that it doesn't warn when there's an un-annotated
> > intermediary function. Even when that function is in the same TU.
>
> Hm.  Couldn't we make "calling an un-annotated function" be a violation
> in itself?

I don't see a way to do that with these annotations, unfortunately.

https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
https://clang.llvm.org/docs/AttributeReference.html#acquire-capability-acquire-shared-capability


> Certainly in the case of spinlocks, what we want is pretty
> nearly a total ban on calling anything at all.  I wouldn't cry too hard
> about having a similar policy for signal handlers.

It'd be interesting to try and see how invasive that'd be, if it were
possible to enforce. But...

Greetings,

Andres Freund



pgsql-hackers by date:

Previous
From: Alvaro Herrera
Date:
Subject: Re: Add A Glossary
Next
From: Dave Cramer
Date:
Subject: Re: language cleanups in code and docs