Re: Avoid memory leaks during base backups

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>, Cary Huang <cary.huang@highgo.ca>, pgsql-hackers@lists.postgresql.org
Date: 2022-10-20T16:18:30Z
Lists: pgsql-hackers
On Thu, Oct 20, 2022 at 6:47 AM Bharath Rupireddy
<bharath.rupireddyforpostgres@gmail.com> wrote:
> I tried implementing this, please see the attached v7 patch.

I haven't checked this in detail but it looks much more reasonable in
terms of code footprint. However, we should, I think, set backup_state
= NULL and tablespace_map = NULL before deleting the memory context.
As you have it, I believe that if backup_state = (BackupState *)
palloc0(sizeof(BackupState)) fails -- say due to running out of memory
-- then those variables could end up pointing to garbage because the
context had already been reset before initializing them. I don't know
whether it's possible for that to cause any concrete harm, but nulling
out the pointers seems like cheap insurance.

-- 
Robert Haas
EDB: http://www.enterprisedb.com



Commits

  1. Improve memory handling across SQL-callable backup functions