Bug 52725 - Frequent CSC hangs when invoked on xamarin-android builder
Summary: Frequent CSC hangs when invoked on xamarin-android builder
Status: RESOLVED FIXED
Alias: None
Product: Runtime
Classification: Mono
Component: General ()
Version: master
Hardware: PC Mac OS
: --- normal
Target Milestone: ---
Assignee: Zoltan Varga
URL:
Depends on:
Blocks:
 
Reported: 2017-02-23 22:31 UTC by Andi McClure
Modified: 2017-03-07 17:10 UTC (History)
4 users (show)

Tags: 2017-02
Is this bug a regression?: ---
Last known good build:


Attachments
crash stack (237.16 KB, text/plain)
2017-02-23 22:31 UTC, Andi McClure
Details


Notice (2018-05-24): bugzilla.xamarin.com is now in read-only mode.

Please join us on Visual Studio Developer Community and in the Xamarin and Mono organizations on GitHub to continue tracking issues. Bugzilla will remain available for reference in read-only mode. We will continue to work on open Bugzilla bugs, copy them to the new locations as needed for follow-up, and add the new items under Related Links.

Our sincere thanks to everyone who has contributed on this bug tracker over the years. Thanks also for your understanding as we make these adjustments and improvements for the future.


Please create a new report on GitHub or Developer Community with your current version information, steps to reproduce, and relevant error messages or log files if you are hitting an issue that looks similar to this resolved bug and you do not yet see a matching new report.

Related Links:
Status:
RESOLVED FIXED

Description Andi McClure 2017-02-23 22:31:43 UTC
Created attachment 19936 [details]
crash stack

When the xamarin-android builder runs with the 2017-02 toolchain, on maybe 1 out of every 2 build attempts, at least one csc invocation hangs permanently. This problem does not reproduce on my development laptop.

Marek thinks this is linked to bugzilla #52258, however, that was a crash, and I'm confused what the status of #52258 is anyway.

The hang looks to me like a managed deadlock. If we halt the affected process, it seems to be inside managed threads and doing work.

For example, here is one set of managed stacks obtained with kill -QUIT:

https://gist.github.com/jonpryor/2bdeaa70cc3b22c9a31ba4e5973d7b41

For another, here's the results of a kill -ABORT from a different run, plus my results of attaching with LLDB:

[see attachment]
Comment 1 Zoltan Varga 2017-03-02 22:24:17 UTC
_Hopefully_ fixed by:
https://github.com/mono/mono/commit/f0c0314e4d132ffa8114af404a8ea5c21ebe0c87
Comment 2 Zoltan Varga 2017-03-07 17:10:12 UTC
Should be fixed.