pgsql: Make GetSnapshotData() more resilient on out-of-memory errors - Mailing list pgsql-committers

From Michael Paquier
Subject pgsql: Make GetSnapshotData() more resilient on out-of-memory errors
Date
Msg-id E1wa54y-000p5X-0o@gemulon.postgresql.org
Whole thread
List pgsql-committers
Make GetSnapshotData() more resilient on out-of-memory errors

If the allocation of Snapshot->subxip fails, a follow-up call of
GetSnapshotData() would see a partially-initialized snapshot, causing a
NULL dereference on reentry when using "subxip" because only "xip" would
be allocated.  In the event of an out-of-memory error when allocating
"subxip", "xip" is now reset before throwing an ERROR, so as Snapshots
can be allocated and handled gracefully on retry.

This problem is unlikely going to show up in practice, so no backpatch.

Reported-by: Alexander Lakhin <exclusion@gmail.com>
Author: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/e77acaac-a1b3-40b3-99ee-5769b4e453e4@gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/29fb598b9cad898ef851b9a7704f980218057562

Modified Files
--------------
src/backend/storage/ipc/procarray.c | 8 ++++++++
1 file changed, 8 insertions(+)


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