diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2015-09-20 16:48:44 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2015-09-20 16:48:44 -0400 |
| commit | ac0c71228fe7e44d9eba130df9bbbb5c2bfa9faa (patch) | |
| tree | 72f13118f5f98c34abca451013955f5bf97e646a | |
| parent | afca291cc258597098fd01c899a4da49d3896562 (diff) | |
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 1785acebf2ed14fd66955e2d9a55d77a025f418d), 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.
| -rw-r--r-- | src/backend/storage/lmgr/lock.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 65726196d00..4dd78f91138 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -744,7 +744,7 @@ LockAcquireExtended(const LOCKTAG *locktag, locallock->numLockOwners = 0; locallock->maxLockOwners = 8; locallock->holdsStrongLockCount = FALSE; - locallock->lockOwners = NULL; + locallock->lockOwners = NULL; /* in case next line fails */ locallock->lockOwners = (LOCALLOCKOWNER *) MemoryContextAlloc(TopMemoryContext, locallock->maxLockOwners * sizeof(LOCALLOCKOWNER)); @@ -1213,7 +1213,9 @@ RemoveLocalLock(LOCALLOCK *locallock) if (locallock->lockOwners[i].owner != NULL) ResourceOwnerForgetLock(locallock->lockOwners[i].owner, locallock); } - pfree(locallock->lockOwners); + locallock->numLockOwners = 0; + if (locallock->lockOwners != NULL) + pfree(locallock->lockOwners); locallock->lockOwners = NULL; if (locallock->holdsStrongLockCount) |