Обсуждение: Finding memory corruption in an extension
An extension I'm creating is causing Postgres to crash, almost certainly due to memory corruption. I am using palloc0/pfree, calling SET_VARSIZE, and generally following the procedures documented here: https://www.postgresql.org/docs/12/xfunc-c.html. I am also testing my code outside of Postgres (using alloc/free instead of palloc0/pfree), and valgrind is not finding any corruption or leaks.
The crash is not completely reproducible, but when it does happen, it's pretty fast -- create a table, insert a couple of rows, explain a query. (My goal is to create a GIN index on my datatype, but this crash occurs without the index.)
The crash is not completely reproducible, but when it does happen, it's pretty fast -- create a table, insert a couple of rows, explain a query. (My goal is to create a GIN index on my datatype, but this crash occurs without the index.)
I'm interested in advice on how to go about hunting down my problem. Something along the lines of a debugging malloc, or valgrind, for Postgres.
Jack Orenstein
Hi
pá 8. 1. 2021 v 18:48 odesílatel Jack Orenstein <jao@geophile.com> napsal:
An extension I'm creating is causing Postgres to crash, almost certainly due to memory corruption. I am using palloc0/pfree, calling SET_VARSIZE, and generally following the procedures documented here: https://www.postgresql.org/docs/12/xfunc-c.html. I am also testing my code outside of Postgres (using alloc/free instead of palloc0/pfree), and valgrind is not finding any corruption or leaks.
The crash is not completely reproducible, but when it does happen, it's pretty fast -- create a table, insert a couple of rows, explain a query. (My goal is to create a GIN index on my datatype, but this crash occurs without the index.)I'm interested in advice on how to go about hunting down my problem. Something along the lines of a debugging malloc, or valgrind, for Postgres.
The basic feature is using postgres compiled with --enable-cassert flag. It does lot of checks of memory corruptions
Regards
Pavel
Jack Orenstein
Pavel Stehule <pavel.stehule@gmail.com> writes: > pá 8. 1. 2021 v 18:48 odesílatel Jack Orenstein <jao@geophile.com> napsal: >> I'm interested in advice on how to go about hunting down my problem. >> Something along the lines of a debugging malloc, or valgrind, for Postgres. > The basic feature is using postgres compiled with --enable-cassert flag. It > does lot of checks of memory corruptions Yeah, you should absolutely use --enable-cassert when working on C code. If you need valgrind, there's advice about how to run it at https://wiki.postgresql.org/wiki/Valgrind regards, tom lane