Bug 39786 - Hard Crash: poll_event_wait: mono_poll () failed, error (10) No child processes
Summary: Hard Crash: poll_event_wait: mono_poll () failed, error (10) No child processes
Status: NEW
Alias: None
Product: Runtime
Classification: Mono
Component: General (show other bugs)
Version: 4.2.0 (C6)
Hardware: PC Linux
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2016-03-19 11:58 UTC by Marko
Modified: 2017-01-16 02:25 UTC (History)
4 users (show)

See Also:
Is this bug a regression?: ---
Last known good build:


Description Marko 2016-03-19 11:58:50 UTC
I have a hard crash on Linux (Debian 7) with the mono runtime (4.2). I'm spawning a lot of short running processes (~5 seconds, ~25 in parallel) with Process.Start and after some time, the mono runtime crashes with an error.

I don't know what's wrong. I would like to help resolve this issue, if someone guides me to get a better crash report.

poll_event_wait: mono_poll () failed, error (10) No child processes


Native stacktrace:

<------>mono() [0x49d56c]
<------>/lib/x86_64-linux-gnu/libpthread.so.0(+0xf8d0) [0x7f32cf1bb8d0]
<------>/lib/x86_64-linux-gnu/libc.so.6(gsignal+0x37) [0x7f32cee38107]
<------>/lib/x86_64-linux-gnu/libc.so.6(abort+0x148) [0x7f32cee394e8]
<------>mono() [0x62abd9]
<------>mono() [0x62ade7]
<------>mono() [0x62ae92]
<------>mono() [0x589afe]
<------>mono() [0x58a66a]
<------>mono() [0x584343]
<------>mono() [0x6245d6]
<------>/lib/x86_64-linux-gnu/libpthread.so.0(+0x80a4) [0x7f32cf1b40a4]
<------>/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d) [0x7f32ceee8ccd]

Debug info from gdb:

Got a SIGABRT while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries.
used by your application.
Comment 1 jacotb 2016-09-13 07:43:37 UTC
Can confirm. This is a rare crash that happens when a lot of httplistener requests are processed, and at the same time some IO writes.

I haven't been able to pin down what part of my code it originates from.
Comment 2 jacotb 2016-09-13 07:44:45 UTC
If someone could teach me how to debug this, I'd be happy to do so.
Comment 3 JaredNZ 2017-01-16 02:25:09 UTC
+1; Ubuntu 16.04 and latest mono (4.6.2) reliably causes total application failure in use case of 100+ process spawns.

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