From: | Heikki Linnakangas <heikki(dot)linnakangas(at)iki(dot)fi> |
---|---|
To: | pgsql-committers(at)postgresql(dot)org |
Subject: | pgsql: Fix RBM_ZERO_AND_LOCK mode to not acquire lock on local buffers. |
Date: | 2015-05-13 07:16:51 |
Message-ID: | E1YsQuR-0001Bu-Bl@gemulon.postgresql.org |
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Thread: | |
Lists: | pgsql-committers |
Fix RBM_ZERO_AND_LOCK mode to not acquire lock on local buffers.
Commit 81c45081 introduced a new RBM_ZERO_AND_LOCK mode to ReadBuffer, which
takes a lock on the buffer before zeroing it. However, you cannot take a
lock on a local buffer, and you got a segfault instead. The version of that
patch committed to master included a check for !isLocalBuf, and therefore
didn't crash, but oddly I missed that in the back-patched versions. This
patch adds that check to the back-branches too.
RBM_ZERO_AND_LOCK mode is only used during WAL replay, and in hash indexes.
WAL replay only deals with shared buffers, so the only way to trigger the
bug is with a temporary hash index.
Reported by Artem Ignatyev, analysis by Tom Lane.
Branch
------
REL9_1_STABLE
Details
-------
http://git.postgresql.org/pg/commitdiff/f6c4a8690c9374be828c7fca4c2b6199f39b27fa
Modified Files
--------------
src/backend/storage/buffer/bufmgr.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
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