Be sure to release proc->backendLock after SetupLockInTable() failure.

The various places that transferred fast-path locks to the main lock table
neglected to release the PGPROC's backendLock if SetupLockInTable failed
due to being out of shared memory.  In most cases this is no big deal since
ensuing error cleanup would release all held LWLocks anyway.  But there are
some hot-standby functions that don't consider failure of
FastPathTransferRelationLocks to be a hard error, and in those cases this
oversight could lead to system lockup.  For consistency, make all of these
places look the same as FastPathTransferRelationLocks.

Noted while looking for the cause of Dan Wood's bugs --- this wasn't it,
but it's a bug anyway.

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index a6f371566abb16da957234af1919310451467beb..3e761027946aa6d9ee8a0bf9d27ad0e33e2f682c 100644 (file)
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -2537,6 +2537,7 @@ FastPathTransferRelationLocks(LockMethod lockMethodTable, const LOCKTAG *locktag
                                if (!proclock)
                                {
                                        LWLockRelease(partitionLock);
+                                       LWLockRelease(proc->backendLock);
                                        return false;
                                }
                                GrantLock(proclock->tag.myLock, proclock, lockmode);
@@ -2592,6 +2593,7 @@ FastPathGetRelationLockEntry(LOCALLOCK *locallock)
                if (!proclock)
                {
                        LWLockRelease(partitionLock);
+                       LWLockRelease(MyProc->backendLock);
                        ereport(ERROR,
                                        (errcode(ERRCODE_OUT_OF_MEMORY),
                                         errmsg("out of shared memory"),
@@ -4055,6 +4057,7 @@ VirtualXactLock(VirtualTransactionId vxid, bool wait)
                if (!proclock)
                {
                        LWLockRelease(partitionLock);
+                       LWLockRelease(proc->backendLock);
                        ereport(ERROR,
                                        (errcode(ERRCODE_OUT_OF_MEMORY),
                                         errmsg("out of shared memory"),