rdelaage
/
postgresql
mirror of https://git.postgresql.org/git/postgresql.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

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
This commit is contained in:
Thomas Munro 2020-02-01 14:29:13 +13:00
parent f521ef0ae3
commit 95936c795b
1 changed files with 9 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
src/backend/storage/ipc/dsm.c
View File

@ -496,9 +496,18 @@ dsm_create(Size size)
/* 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);
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
errmsg("too many dynamic shared memory segments")));
}
/* Enter the handle into a new array slot. */
dsm_control->item[nitems].handle = seg->handle;