[Mono-bugs] [Bug 642780] New: Mono debugger thread crashes when app exits quickly

[bugzilla_noreply at novell.com]

https://bugzilla.novell.com/show_bug.cgi?id=642780

https://bugzilla.novell.com/show_bug.cgi?id=642780#c0


           Summary: Mono debugger thread crashes when app exits quickly
    Classification: Mono
           Product: Mono: Runtime
           Version: SVN
          Platform: PC
        OS/Version: Windows 7
            Status: NEW
          Severity: Normal
          Priority: P5 - None
         Component: debug
        AssignedTo: martin at novell.com
        ReportedBy: daryl at rd.scei.sony.co.jp
         QAContact: mono-bugs at lists.ximian.com
          Found By: ---
           Blocker: ---


User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_4; en-US)
AppleWebKit/534.3 (KHTML, like Gecko) Chrome/6.0.472.63 Safari/534.3

If the user terminates the mono app when launched from the monodevelop
debugger, sometimes mono crashes. This appears to be the result of a race
condition where a mutex is destroyed before it is finished with.

There appears to be a race condition in debugger in the functions
mono_debugger_agent_cleanup() and debugger_thread(). The following routine does
not appear to wait until debugger_thread_exited == true. The mutex
"debugger_thread_exited_mutex" will remain in use unless debugger_thread_exited
== true.

mono_mutex_lock (&debugger_thread_exited_mutex);
if (!debugger_thread_exited) {
#ifdef HOST_WIN32
    if (WAIT_TIMEOUT == WaitForSingleObject(debugger_thread_exited_cond, 0)) {
        mono_mutex_unlock (&debugger_thread_exited_mutex);
        Sleep(0);
        mono_mutex_lock (&debugger_thread_exited_mutex);
    }
#else
    mono_cond_wait (&debugger_thread_exited_cond,
&debugger_thread_exited_mutex);
#endif
}
mono_mutex_unlock (&debugger_thread_exited_mutex);


Reproducible: Always

Steps to Reproduce:
1.Debug process in monodevelop
2.Immediately terminate C# program

Actual Results:  
Exception should be generated due to debugger_thread trying to lock a deleted
mutex

Expected Results:  
no exception should occur

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