From 637e86ecc5e4fcc5447b67d83337bc8752a40a52 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Mon, 16 Oct 2023 10:43:47 +1300 Subject: [PATCH] Acquire ControlFileLock in relevant SQL functions. Commit dc7d70ea added functions that read the control file, but didn't acquire ControlFileLock. With unlucky timing, file systems that have weak interlocking like ext4 and ntfs could expose partially overwritten contents, and the checksum would fail. Back-patch to all supported releases. Reviewed-by: David Steele Reviewed-by: Anton A. Melnikov Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/20221123014224.xisi44byq3cf5psi%40awork3.anarazel.de --- src/backend/utils/misc/pg_controldata.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/src/backend/utils/misc/pg_controldata.c b/src/backend/utils/misc/pg_controldata.c index b42921800b7..df9526fcdd9 100644 --- a/src/backend/utils/misc/pg_controldata.c +++ b/src/backend/utils/misc/pg_controldata.c @@ -24,6 +24,7 @@ #include "common/controldata_utils.h" #include "funcapi.h" #include "miscadmin.h" +#include "storage/lwlock.h" #include "utils/builtins.h" #include "utils/pg_lsn.h" #include "utils/timestamp.h" @@ -54,7 +55,9 @@ pg_control_system(PG_FUNCTION_ARGS) tupdesc = BlessTupleDesc(tupdesc); /* read the control file */ + LWLockAcquire(ControlFileLock, LW_SHARED); ControlFile = get_controlfile(DataDir, &crc_ok); + LWLockRelease(ControlFileLock); if (!crc_ok) ereport(ERROR, (errmsg("calculated CRC checksum does not match value stored in file"))); @@ -132,7 +135,9 @@ pg_control_checkpoint(PG_FUNCTION_ARGS) tupdesc = BlessTupleDesc(tupdesc); /* Read the control file. */ + LWLockAcquire(ControlFileLock, LW_SHARED); ControlFile = get_controlfile(DataDir, &crc_ok); + LWLockRelease(ControlFileLock); if (!crc_ok) ereport(ERROR, (errmsg("calculated CRC checksum does not match value stored in file"))); @@ -236,7 +241,9 @@ pg_control_recovery(PG_FUNCTION_ARGS) tupdesc = BlessTupleDesc(tupdesc); /* read the control file */ + LWLockAcquire(ControlFileLock, LW_SHARED); ControlFile = get_controlfile(DataDir, &crc_ok); + LWLockRelease(ControlFileLock); if (!crc_ok) ereport(ERROR, (errmsg("calculated CRC checksum does not match value stored in file"))); @@ -303,7 +310,9 @@ pg_control_init(PG_FUNCTION_ARGS) tupdesc = BlessTupleDesc(tupdesc); /* read the control file */ + LWLockAcquire(ControlFileLock, LW_SHARED); ControlFile = get_controlfile(DataDir, &crc_ok); + LWLockRelease(ControlFileLock); if (!crc_ok) ereport(ERROR, (errmsg("calculated CRC checksum does not match value stored in file"))); -- 2.39.5