Horton

Re: VM corruption on standby

Andrey Borodin <x4mmm@yandex-team.ru>

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From: Andrey Borodin <x4mmm@yandex-team.ru>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Kirill Reshke <reshkekirill@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Melanie Plageman <melanieplageman@gmail.com>
Date: 2025-09-03T06:47:28Z
Lists: pgsql-hackers 

> On 3 Sep 2025, at 11:37, Alexander Korotkov <aekorotkov@gmail.com> wrote:
> 
> Could you, please, recheck?

That patch also adds CondVar sleep in critical section. That patch is how we understood that such sleep is dangerous.

Actual patch to deteact a problem is much simpler:
```
diff --git a/src/backend/storage/ipc/waiteventset.c
b/src/backend/storage/ipc/waiteventset.c
index 7c0e66900f9..e89e1d115cb 100644
--- a/src/backend/storage/ipc/waiteventset.c
+++ b/src/backend/storage/ipc/waiteventset.c
@@ -1044,6 +1044,7 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
       long            cur_timeout = -1;

       Assert(nevents > 0);
+       Assert(CritSectionCount == 0);

       /*
        * Initialize timeout if requested.  We must record the current time so
```

Though it will fail in multixact test.


Best regards, Andrey Borodin.