Bug 42191

Summary: sdb deadlocks all the time while XS debugs XS
Product: [Mono] Runtime Reporter: Alan McGovern <alan>
Component: DebuggerAssignee: Zoltan Varga <vargaz>
Severity: normal CC: chandankumar1324, kumpera, mono-bugs+mono, mono-bugs+runtime
Priority: High    
Version: 4.5.X   
Target Milestone: 4.6.0 (C8)   
Hardware: PC   
OS: Mac OS   
Tags: Is this bug a regression?: ---
Last known good build:

Description Alan McGovern 2016-06-27 14:09:23 UTC
Mono JIT compiler version 4.5.1 (mono-4.5.1-branch/3581d0d Wed Jun 22 10:59:32 EDT 2016)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
	TLS:           normal
	SIGSEGV:       altstack
	Notification:  kqueue
	Architecture:  x86
	Disabled:      none
	Misc:          softdebug 
	LLVM:          yes(3.6.0svn-mono-master/a173357)
	GC:            sgen

I'm using a mono 4.5.1 preview release and I find that if i debug XS inside XS the debugee hangs frequently when stepping over/into methods.

Example output from lldb while trying to step and the process has hung: https://gist.github.com/alanmcgovern/656e8310b502645b789d64fcc9a956c8
Comment 1 Alan McGovern 2016-06-30 14:03:28 UTC
Here's a second lldb trace:
Comment 2 Alan McGovern 2016-06-30 14:04:21 UTC
The second trace is a deadlock on startup before i even try to do any single stepping. XS doesn't even have time to open it's main screen when this deadlock occurs.
Comment 3 Zoltan Varga 2016-06-30 21:48:00 UTC
Should be fixed by mono master 44fed99f094d4b87ff898b9ada186514e9b47c14/4.5.1 branch 00bb13f6a549bafe98d1c1bdac4ed01e23e33952.
Comment 4 Alan McGovern 2016-07-01 15:49:49 UTC
I can confirm it's fixed with tip of 4.5.1. No more deadlocks starting XS with SDB attached! Thanks!