On Fri, Jul 28, 2023 at 8:54 AM Michael Paquier <mich...@paquier.xyz> wrote: > > Hi all, > > While digging into the LWLock code, I have noticed that > GetNamedLWLockTranche() assumes that its caller should hold the LWLock > AddinShmemInitLock to prevent any kind of race conditions when > initializing shmem areas, but we don't make sure that's the case. > > The sole caller of GetNamedLWLockTranche() in core respects that, but > out-of-core code may not be that careful. How about adding an > assertion based on LWLockHeldByMeInMode() to make sure that the > ShmemInit lock is taken when this routine is called, like in the > attached?
+1 for asserting that the caller holds AddinShmemInitLock to prevent reads while someone else is adding their LWLocks. + Assert(LWLockHeldByMeInMode(AddinShmemInitLock, LW_EXCLUSIVE)); Why to block multiple readers (if at all there exists any), with LWLockHeldByMeInMode(..., LW_EXCLUSIVE)? I think Assert(LWLockHeldByMe(AddinShmemInitLock)); suffices in GetNamedLWLockTranche. -- Bharath Rupireddy PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
