From ed28b0f2cac246e9dad669fd59631b8f9e5db2f5 Mon Sep 17 00:00:00 2001
From: Ben Gamari <ben@smart-cactus.org>
Date: Tue, 18 Jul 2023 15:45:12 -0400
Subject: [PATCH] rts/win32: Ensure reliability of IO manager shutdown
When the Win32 threaded IO manager shuts down, `ioManagerDie` sends an
`IO_MANAGER_DIE` event to the IO manager thread using the
`io_manager_event` event object. Finally, it will closes the event object,
and invalidate `io_manager_event`.
Previously, `readIOManagerEvent` would see that `io_manager_event` is
invalid and return `0`, suggesting that everything is right with the
world. This meant that if `ioManagerDie` invalidated the handle before
the event manager was blocked on the event we would end up in a
situation where the event manager would never realize it was asked to
shut down.
Fix this by ensuring that `readIOManagerEvent` instead returns
`IO_MANAGER_DIE` when we detect that the event object has been
invalidated by `ioManagerDie`.
Fixes #23691.
---
rts/win32/ThrIOManager.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/rts/win32/ThrIOManager.c b/rts/win32/ThrIOManager.c
index 6bbf65a45f5..72806456687 100644
--- a/rts/win32/ThrIOManager.c
+++ b/rts/win32/ThrIOManager.c
@@ -79,7 +79,9 @@ readIOManagerEvent (void)
}
}
} else {
- res = 0;
+ // Making it here means that we have hit ioManagerDie, which
+ // closed our event object.
+ res = IO_MANAGER_DIE;
}
OS_RELEASE_LOCK(&event_buf_mutex);
--
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