pgsql: Mark buffers as defined to Valgrind consistently. - Mailing list pgsql-committers

From Peter Geoghegan
Subject pgsql: Mark buffers as defined to Valgrind consistently.
Date
Msg-id E1jxCTX-0006hb-Uy@gemulon.postgresql.org
Whole thread Raw
List pgsql-committers
Mark buffers as defined to Valgrind consistently.

Make PinBuffer() mark buffers as defined to Valgrind unconditionally,
including when the buffer header spinlock must be acquired.  Failure to
handle that case could lead to false positive reports from Valgrind.

This theoretically creates a risk that we'll mark buffers defined even
when external callers don't end up with a buffer pin.  That seems
perfectly acceptable, though, since in general we make no guarantees
about buffers that are unsafe to access being reliably marked as unsafe.

Oversight in commit 1e0dfd16, which added valgrind buffer access
instrumentation.

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/46ef520b9566d9eccb095ceafa53e5c305cf80b9

Modified Files
--------------
src/backend/storage/buffer/bufmgr.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)


pgsql-committers by date:

Previous
From: Tom Lane
Date:
Subject: pgsql: Correctly mark pg_subscription.subslotname as nullable.
Next
From: Peter Geoghegan
Date:
Subject: pgsql: Avoid harmless Valgrind no-buffer-pin errors.