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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 | 3d3bc2905f2ed6a4858501031c086383be7bcf6a (patch) | |
| tree | 2bd96f5bcfb4d164dffe5f5963277dd1390d9953 /src/backend | |
| parent | b46f5ebd9c8f6ec37e27c56749266fc2e362902b (diff) | |
| download | postgresql-3d3bc2905f2ed6a4858501031c086383be7bcf6a.tar.gz postgresql-3d3bc2905f2ed6a4858501031c086383be7bcf6a.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/backend')
| -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 1eb2d4b68da..c377d384b76 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -753,7 +753,7 @@ 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)); @@ -1222,7 +1222,9 @@ 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) |