Re: [HACKERS] SIGSEGV in BRIN autosummarize

Justin Pryzby wrote:

> #1  0x00000000006a52e9 in perform_work_item (workitem=0x7f8ad1f94824) at autovacuum.c:2676
>         cur_datname = 0x298c740 "no 1 :vartype 1184 :vartypmod -1 :varcollid 0 :varlevelsup 0 :varnoold 1 :varoattno
1:location 146} {CONST :consttype 1184 :consttypmod -1 :constcollid 0 :constlen 8 :constbyval true :constisnull
fal"...
>         cur_nspname = 0x298c728 "s ({VAR :varno 1 :varattno 1 :vartype 1184 :vartypmod -1 :varcollid 0 :varlevelsup 0
:varnoold1 :varoattno 1 :location 146} {CONST :consttype 1184 :consttypmod -1 :constcollid 0 :constlen 8 :constbyv"...
 
>         cur_relname = 0x298cd68 "cdrs_eric_msc_sms_2017_10_14_startofcharge_idx"
>         __func__ = "perform_work_item"

cur_datname here seems corrupted -- it points halfway into cur_nspname,
which is also a corrupt value.  And I think that's because we're not
checking that the namespace OID is a valid value before calling
get_namespace_name on it.  And I'm betting that these values are all not
what we expect, because we're not checking that we're in the correct
database before trying to execute the work item.  I don't quite
understand how this results in an invalid string rather than just a
NULL, as I would have expected.

Anyway, can give this patch a try?

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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