| From: | Heikki Linnakangas <heikki(dot)linnakangas(at)iki(dot)fi> |
|---|---|
| To: | pgsql-committers(at)lists(dot)postgresql(dot)org |
| Subject: | pgsql: Prevent race condition while reading relmapper file. |
| Date: | 2021-06-24 07:46:43 |
| Message-ID: | E1lwK4R-0008TR-EW@gemulon.postgresql.org |
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| Lists: | pgsql-committers |
Prevent race condition while reading relmapper file.
Contrary to the comment here, POSIX does not guarantee atomicity of a
read(), if another process calls write() concurrently. Or at least Linux
does not. Add locking to load_relmap_file() to avoid the race condition.
Fixes bug #17064. Thanks to Alexander Lakhin for the report and test case.
Backpatch-through: 9.6, all supported versions.
Discussion: https://www.postgresql.org/message-id/17064-bb0d7904ef72add3@postgresql.org
Branch
------
REL_10_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/a5eacd86b71542d5e377d1fef628866dae859809
Modified Files
--------------
src/backend/utils/cache/relmapper.c | 34 ++++++++++++++++++++--------------
1 file changed, 20 insertions(+), 14 deletions(-)
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