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| author | Thomas Munro <tmunro@postgresql.org> | 2021-04-13 12:34:25 +1200 |
|---|---|---|
| committer | Thomas Munro <tmunro@postgresql.org> | 2021-04-13 13:02:56 +1200 |
| commit | b1df6b696b759f00ebbf02e6de64e259d4be5785 (patch) | |
| tree | 1f87911fa68e9749b71cae2524322dbc30ed0c01 | |
| parent | 885a87641930778d9580fdf0656af24e3f52d276 (diff) | |
| download | postgresql-b1df6b696b759f00ebbf02e6de64e259d4be5785.tar.gz postgresql-b1df6b696b759f00ebbf02e6de64e259d4be5785.zip | |
Fix potential SSI hazard in heap_update().
Commit 6f38d4dac38 failed to heed a warning about the stability of the
value pointed to by "otid". The caller is allowed to pass in a pointer to
newtup->t_self, which will be updated during the execution of the
function. Instead, the SSI check should use the value we copy into
oldtup.t_self near the top of the function.
Not a live bug, because newtup->t_self doesn't really get updated until
a bit later, but it was confusing and broke the rule established by the
comment.
Back-patch to 13.
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/2689164.1618160085%40sss.pgh.pa.us
| -rw-r--r-- | src/backend/access/heap/heapam.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 03d4abc938b..548720021ed 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -3900,7 +3900,8 @@ l2: * will include checking the relation level, there is no benefit to a * separate check for the new tuple. */ - CheckForSerializableConflictIn(relation, otid, BufferGetBlockNumber(buffer)); + CheckForSerializableConflictIn(relation, &oldtup.t_self, + BufferGetBlockNumber(buffer)); /* * At this point newbuf and buffer are both pinned and locked, and newbuf |