public inbox for [email protected]  
help / color / mirror / Atom feed
From: Michael Paquier <[email protected]>
To: [email protected]
Subject: pgsql: Fix memory allocation size in RegisterExtensionExplainOption()
Date: Mon, 02 Mar 2026 04:15:24 +0000
Message-ID: <[email protected]> (raw)

Fix memory allocation size in RegisterExtensionExplainOption()

The allocations used for the static array ExplainExtensionOptionArray,
that tracks a set of ExplainExtensionOption, used "char *" instead of
ExplainExtensionOption as the memory size consumed by one element,
underestimating the memory required by half.

The initial allocation of ExplainExtensionNameArray wants to hold 16
elements before being reallocated, and with "char *" it meant that there
was enough space only for 8 ExplainExtensionOption elements, 16 bytes
required for each element.  The backend would crash once one tries to
register a 9th EXPLAIN option.

As far as I can see, the allocation formulas of GetExplainExtensionId()
have been copy-pasted to RegisterExtensionExplainOption(), but the
internal maths of the copy were not adjusted accordingly.

Oversight in c65bc2e1d14a.

Author: Joel Jacobson <[email protected]>
Discussion: https://postgr.es/m/[email protected]
Backpatch-through: 18

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/f7dc17aa9116a90a235ecf77c46afbbd6b6f8fbc

Modified Files
--------------
src/backend/commands/explain_state.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)



view thread (2+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected]
  Subject: Re: pgsql: Fix memory allocation size in RegisterExtensionExplainOption()
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox