Horton

Re: elog(DEBUG2 in SpinLocked section.

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Michael Paquier <michael@paquier.xyz>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, masao.fujii@oss.nttdata.com, amit.kapila16@gmail.com, pasim@vmware.com, pgsql-hackers@lists.postgresql.org
Date: 2020-06-16T23:46:29Z
Lists: pgsql-hackers 
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?  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.  (The postmaster's
handlers would have to be an exception for now.)

			regards, tom lane

Commits

  1. Fix instance of elog() called while holding a spinlock

  2. Don't call palloc() while holding a spinlock, either.

  3. Don't call elog() while holding spinlock.