Re: BUG #16329: Valgrind detects an invalid read when building a gistindex with buffering

Hello hackers,
30.03.2020 08:00, Alexander Lakhin wrote:
> 30.03.2020 00:00, PG Bug reporting form wrote:
>> The following bug has been logged on the website:
>>
>> Bug reference:      16329
>> Logged by:          Alexander Lakhin
>> Email address:      exclusion@gmail.com
>> PostgreSQL version: 12.2
>> Operating system:   Ubuntu 18.04
>> Description:        
>>
>> Running the following query under valgrind:
>> create table gist_point_tbl(id int4, p point);
>> insert into gist_point_tbl (id, p)
>> select g, point(g*10+1, g*10+1) from generate_series(1, 30000) g;
>> create index gist_pointidx2 on gist_point_tbl using gist(p) with (buffering
>> = on, fillfactor=50);
>>
>> leads to a memory access error:
>> ==00:00:00:08.755 18585== Invalid read of size 2
>> ==00:00:00:08.756 18585==    at 0x1F94CA: gistBuildCallback
>> (gistbuild.c:495)
>>
Please look at the patch that modifies the gist regression test to make
the issue visible and fixes it by avoiding access to the memory context
that can be reset in gistProcessEmptyingQueue().

Best regards,
Alexander