Horton

Re: PostgreSQL crashes with SIGSEGV

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Aleksandr Parfenov <a.parfenov@postgrespro.ru>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2018-01-17T20:41:13Z
Lists: pgsql-bugs, pgsql-hackers 
On Wed, Jan 17, 2018 at 12:31 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Probably not very.  It'd be nice to have it done by the next minor
> releases, ie before 5-Feb ... but given that these bugs are years
> old, missing that deadline would not be catastrophic.

Got it.

>> I'm not sure whether or not we should also apply this
>> still-to-be-written 9.5 patch to 9.4 and 9.3, since those versions
>> don't have grouping sets, and so cannot crash. ISTM that we should
>> leave them alone, since tuplesort has had this problem forever.
>
> +1.  If the problem isn't known to be reproducible in those branches,
> the risk of adding new bugs seems to outweigh any benefit.

You could make the same objection to changing tuplesort_getdatum()
outside of the master branch, though. I think that going back further
than that for the (arguably independent) tuplesort_getdatum() subset
fix might still be a good idea. I wonder where you stand on this.

-- 
Peter Geoghegan

Commits

  1. Fix actual and potential double-frees around tuplesort usage.

  2. Allow the built-in ordered-set aggregates to share transition state.

  3. Avoid integer overflow while sifting-up a heap in tuplesort.c.

  4. Allow avoiding tuple copy within tuplesort_gettupleslot().

  5. Remove should_free arguments to tuplesort routines.

  6. Fix use-after-free around DISTINCT transition function calls.

  7. Reuse abbreviated keys in ordered [set] aggregates.