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| 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 | e32c5f118ec2da80fd76da1241dd721ceb3e9127 (patch) | |
| tree | d14cd3bca3baaa252c0204528e48ddb40e612b75 /src | |
| parent | f38070d630149a98984a7145093e08706ad99828 (diff) | |
| download | postgresql-e32c5f118ec2da80fd76da1241dd721ceb3e9127.tar.gz postgresql-e32c5f118ec2da80fd76da1241dd721ceb3e9127.zip | |
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.
Diffstat (limited to 'src')
| -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 c0dd84b3ba9..3e33bc104d3 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -758,7 +758,7 @@ 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)); @@ -1227,7 +1227,9 @@ 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) |