diff options
| author | Thomas Munro <tmunro@postgresql.org> | 2020-02-01 14:29:13 +1300 |
|---|---|---|
| committer | Thomas Munro <tmunro@postgresql.org> | 2020-02-01 14:29:13 +1300 |
| commit | 93745f1e019543fe7b742d0c5e971aad8d08fd56 (patch) | |
| tree | 0c1b69d9ff932a6047e899c1b905ce0162931a9a | |
| parent | 870ad6a59bbbd95c2dc3cfe67b07d0e079599edf (diff) | |
Fix memory leak on DSM slot exhaustion.
If we attempt to create a DSM segment when no slots are available,
we should return the memory to the operating system. Previously
we did that if the DSM_CREATE_NULL_IF_MAXSEGMENTS flag was
passed in, but we didn't do it if an error was raised. Repair.
Back-patch to 9.4, where DSM segments arrived.
Author: Thomas Munro
Reviewed-by: Robert Haas
Reported-by: Julian Backes
Discussion: https://postgr.es/m/CA%2BhUKGKAAoEw-R4om0d2YM4eqT1eGEi6%3DQot-3ceDR-SLiWVDw%40mail.gmail.com
| -rw-r--r-- | src/backend/storage/ipc/dsm.c | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/src/backend/storage/ipc/dsm.c b/src/backend/storage/ipc/dsm.c index 1ed6ed2b1d1..ef64d083570 100644 --- a/src/backend/storage/ipc/dsm.c +++ b/src/backend/storage/ipc/dsm.c @@ -479,17 +479,16 @@ dsm_create(Size size, int flags) /* Verify that we can support an additional mapping. */ if (nitems >= dsm_control->maxitems) { + LWLockRelease(DynamicSharedMemoryControlLock); + dsm_impl_op(DSM_OP_DESTROY, seg->handle, 0, &seg->impl_private, + &seg->mapped_address, &seg->mapped_size, WARNING); + if (seg->resowner != NULL) + ResourceOwnerForgetDSM(seg->resowner, seg); + dlist_delete(&seg->node); + pfree(seg); + if ((flags & DSM_CREATE_NULL_IF_MAXSEGMENTS) != 0) - { - LWLockRelease(DynamicSharedMemoryControlLock); - dsm_impl_op(DSM_OP_DESTROY, seg->handle, 0, &seg->impl_private, - &seg->mapped_address, &seg->mapped_size, WARNING); - if (seg->resowner != NULL) - ResourceOwnerForgetDSM(seg->resowner, seg); - dlist_delete(&seg->node); - pfree(seg); return NULL; - } ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_RESOURCES), errmsg("too many dynamic shared memory segments"))); |