Be more wary about partially-valid LOCALLOCK data in RemoveLocalLock().
RemoveLocalLock() must consider the possibility that LockAcquireExtended()
failed to palloc the initial space for a locallock's lockOwners array.
I had evidently meant to cope with this hazard when the code was originally
written (commit 1785acebf2
), but missed that
the pfree needed to be protected with an if-test. Just to make sure things
are left in a clean state, reset numLockOwners as well.
Per low-memory testing by Andreas Seltenreich. Back-patch to all supported
branches.
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parent
44297a058e
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@ -644,7 +644,7 @@ LockAcquireExtended(const LOCKTAG *locktag,
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locallock->nLocks = 0;
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locallock->numLockOwners = 0;
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locallock->maxLockOwners = 8;
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locallock->lockOwners = NULL;
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locallock->lockOwners = NULL; /* in case next line fails */
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locallock->lockOwners = (LOCALLOCKOWNER *)
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MemoryContextAlloc(TopMemoryContext,
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locallock->maxLockOwners * sizeof(LOCALLOCKOWNER));
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@ -994,8 +994,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
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static void
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RemoveLocalLock(LOCALLOCK *locallock)
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{
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pfree(locallock->lockOwners);
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locallock->numLockOwners = 0;
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if (locallock->lockOwners != NULL)
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pfree(locallock->lockOwners);
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locallock->lockOwners = NULL;
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if (!hash_search(LockMethodLocalHash,
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(void *) &(locallock->tag),
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HASH_REMOVE, NULL))
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