Horton

BUG #17186: In connect.c, the lock connections_mutex is not correctly released(Line 463) at the return(Line 522)

The Post Office <noreply@postgresql.org>

View thread View on postgr.es
From: PG Bug reporting form <noreply@postgresql.org>
To: pgsql-bugs@lists.postgresql.org
Cc: ryancaicse@gmail.com
Date: 2021-09-10T04:29:36Z
Lists: pgsql-bugs 
The following bug has been logged on the website:

Bug reference:      17186
Logged by:          An improper locking bug due to the unreleased lock connections_mutex in
/ecpg/ecpglib/connect.c
Email address:      ryancaicse@gmail.com
PostgreSQL version: 14beta3
Operating system:   All
Description:        

This is a possible improper locking bug, which can lead to resource leaks
and even deadlock. I am not sure whether it can lead to a security
problem.
The problem is that the lock connections_mutex should be released at the end
of the function. But it not released when conn_keywords == NULL ||
conn_values == NULL (ecpg_alloc got errors and return NULL).
Thank you for your checking.

Locations:
https://github.com/postgres/postgres/blob/c30f54ad732ca5c8762bb68bbe0f51de9137dd72/src/interfaces/ecpg/ecpglib/connect.c#L463
https://github.com/postgres/postgres/blob/c30f54ad732ca5c8762bb68bbe0f51de9137dd72/src/interfaces/ecpg/ecpglib/connect.c#L522

Commits

  1. Fix error handling with threads on OOM in ECPG connection logic

  2. Detect POLLHUP/POLLRDHUP while running queries.