Fix WaitEventSet resource leak in WaitLatchOrSocket().

This function would have the same issue we solved in commit 501cfd07d:
If an error is thrown after calling CreateWaitEventSet(), the file
descriptor (on epoll- or kqueue-based systems) or handles (on Windows)
that the WaitEventSet contains are leaked.

Like that commit, use PG_TRY-PG_FINALLY (PG_TRY-PG_CATCH in v12) to make
sure the WaitEventSet is freed properly.

Back-patch to all supported versions, but as we do not have this issue
in HEAD (cf. commit 50c67c201), no need to apply this patch to it.

Discussion: https://postgr.es/m/CAPmGK16MqdDoD8oatp8SQWaEa4vS3nfQqDN_Sj9YRuu5J3Lj9g%40mail.gmail.com
This commit is contained in:
Etsuro Fujita 2024-04-11 19:05:07 +09:00
parent 5e9d8bed00
commit 0341d4b10e
1 changed files with 44 additions and 35 deletions

View File

@ -374,46 +374,55 @@ WaitLatchOrSocket(Latch *latch, int wakeEvents, pgsocket sock,
WaitEvent event;
WaitEventSet *set = CreateWaitEventSet(CurrentMemoryContext, 3);
if (wakeEvents & WL_TIMEOUT)
Assert(timeout >= 0);
else
timeout = -1;
if (wakeEvents & WL_LATCH_SET)
AddWaitEventToSet(set, WL_LATCH_SET, PGINVALID_SOCKET,
latch, NULL);
/* Postmaster-managed callers must handle postmaster death somehow. */
Assert(!IsUnderPostmaster ||
(wakeEvents & WL_EXIT_ON_PM_DEATH) ||
(wakeEvents & WL_POSTMASTER_DEATH));
if ((wakeEvents & WL_POSTMASTER_DEATH) && IsUnderPostmaster)
AddWaitEventToSet(set, WL_POSTMASTER_DEATH, PGINVALID_SOCKET,
NULL, NULL);
if ((wakeEvents & WL_EXIT_ON_PM_DEATH) && IsUnderPostmaster)
AddWaitEventToSet(set, WL_EXIT_ON_PM_DEATH, PGINVALID_SOCKET,
NULL, NULL);
if (wakeEvents & WL_SOCKET_MASK)
PG_TRY();
{
int ev;
if (wakeEvents & WL_TIMEOUT)
Assert(timeout >= 0);
else
timeout = -1;
ev = wakeEvents & WL_SOCKET_MASK;
AddWaitEventToSet(set, ev, sock, NULL, NULL);
if (wakeEvents & WL_LATCH_SET)
AddWaitEventToSet(set, WL_LATCH_SET, PGINVALID_SOCKET,
latch, NULL);
/* Postmaster-managed callers must handle postmaster death somehow. */
Assert(!IsUnderPostmaster ||
(wakeEvents & WL_EXIT_ON_PM_DEATH) ||
(wakeEvents & WL_POSTMASTER_DEATH));
if ((wakeEvents & WL_POSTMASTER_DEATH) && IsUnderPostmaster)
AddWaitEventToSet(set, WL_POSTMASTER_DEATH, PGINVALID_SOCKET,
NULL, NULL);
if ((wakeEvents & WL_EXIT_ON_PM_DEATH) && IsUnderPostmaster)
AddWaitEventToSet(set, WL_EXIT_ON_PM_DEATH, PGINVALID_SOCKET,
NULL, NULL);
if (wakeEvents & WL_SOCKET_MASK)
{
int ev;
ev = wakeEvents & WL_SOCKET_MASK;
AddWaitEventToSet(set, ev, sock, NULL, NULL);
}
rc = WaitEventSetWait(set, timeout, &event, 1, wait_event_info);
if (rc == 0)
ret |= WL_TIMEOUT;
else
{
ret |= event.events & (WL_LATCH_SET |
WL_POSTMASTER_DEATH |
WL_SOCKET_MASK);
}
}
rc = WaitEventSetWait(set, timeout, &event, 1, wait_event_info);
if (rc == 0)
ret |= WL_TIMEOUT;
else
PG_CATCH();
{
ret |= event.events & (WL_LATCH_SET |
WL_POSTMASTER_DEATH |
WL_SOCKET_MASK);
FreeWaitEventSet(set);
PG_RE_THROW();
}
PG_END_TRY();
FreeWaitEventSet(set);