IO: Detect closed IO when resuming readable/writable event #8707
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If the IO was closed by other thread while waiting we need to check if it's open or not. If it's closed an IO::Error is raised as a result of the read/write operation as if the IO was has been closed from the beginning. The event_close is now performed before actually closing the underlying file descriptor to prevent libevent accessing it in a closed state. The @closed = true in IO::FileDescriptor needs to happen before the system_close so it is available when the awaiting fibers are woken up.
bcardiff
added
kind:bug
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Looks like your mt_preview build timed out. Is that because of this change? |
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No it's something Process. Running And if the changes in |
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And the CI is happy 🎉 |
RX14
requested changes
Jan 27, 2020
RX14
approved these changes
Jan 27, 2020
jhass
approved these changes
Jan 27, 2020
jacobh0
reviewed
Apr 26, 2020
| @@ -250,7 +250,7 @@ class Socket < IO | |||
| if closed? | |||
| return | |||
| elsif Errno.value == Errno::EAGAIN | |||
| wait_readable | |||
| wait_readable rescue nil | |||
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@bcardiff shouldn't this be rescue return nil ? The loop doesn't break otherwise. accept? no longer times-out trying to accept a connection and just hangs forever
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This should fix some race conditions detected in the preview_mt build.
I think there are still some race conditions in
IO::Eventedsince there is no guarantee that, for example, a thread closes the IO while another thread has already initiated a read operation, succeed thecheck_openinIO::Bufferend#read, but haven't reach the unbuffered_read -> evented_read -> wait_readable.There is currently no mechanism to ensure that the check for open IO holds long enough until the fibers reschedule.
Even without fixing that scenario this PR should improove the current state for MT: