[Mono-osx] Thread/Unknown Metafile Format Problems

[Ron Ducros]

Hi all,

I have recently released a couple of versions of our application on OS X which uses an embedded version of Mono.

Initially this shipped with 2.6.1 embedded - the embedding is done by creating a package using macpack and then moving the resources directory to our Cocoa GUI app and fixing install paths/names with install_name_tool. This approach was recommended by Novell support.

For our first release we occasionally noticed some strange output in console such as:

WARNING **: Unknown metafile format: key 1095062083

This didn't seem to cause any other problems and was very intermittent. I haven't filed a bug on this yet (shame on me sorry!) as it happens in a very large project and I simply haven't been able to give it sufficient time to try and get it down to a simple reproducible test case.

Recently we released a new version of our product that had 2.6.4_3 embedded (as this had bug fixes that we needed). However we seem to have made the above issue worse (assuming they are related).

We now have some customers reporting intermittent crashes - these have the following stack trace:

Thread 29 Crashed:
0   libSystem.B.dylib             	0x95a054be __semwait_signal_nocancel + 10
1   libSystem.B.dylib             	0x95a053a2 nanosleep$NOCANCEL$UNIX2003 + 166
2   libSystem.B.dylib             	0x95a802f2 usleep$NOCANCEL$UNIX2003 + 61
3   libSystem.B.dylib             	0x95aa19a8 abort + 105
4   libglib-2.0.0.dylib           	0x0059c416 g_assertion_message + 253
5   libglib-2.0.0.dylib           	0x0059ca43 g_test_run_suite_internal + 0
6   libmono.0.dylib               	0x003b73b3 small_id_alloc + 949
7   libmono.0.dylib               	0x003b87e7 mono_thread_attach + 341
8   com.livedrive.livedriveapp    	0x0000c6bd -[MonoCommandHandler commandAttachThread] + 108
9   com.livedrive.livedriveapp    	0x0000c870 -[MonoCommandHandler commandStart:] + 48
10  com.livedrive.livedriveapp    	0x0000a9dc -[MonoManager sha256UpdateSize:length:hashID:] + 73
11  com.livedrive.livedriveapp    	0x00028156 -[Sha256Hash generateHash:] + 870
12  com.apple.Foundation          	0x911738dc -[NSThread main] + 45
13  com.apple.Foundation          	0x9117388c __NSThread__main__ + 1499
14  libSystem.B.dylib             	0x959c5a19 _pthread_start + 345
15  libSystem.B.dylib             	0x959c589e thread_start + 34

In our hashing code we spawn a new NSThread which calls into the C# code we are running under mono and these code does a mono_thread_attach/mono_thread_detach for each thread we spawn (on the Mac side).

I must admit to being a little puzzled at seeing the g_test_run_suite_internal but that does tie in with the first issue (where Novell support confirmed this message should only be coming from the Mono unit test code).

Doing a google search for g_test_run_suite_internal only finds someone with a similar crash and http://bugzilla.novell.com/show_bug.cgi?id=445610 (which is quite old and shows a similar crash stacktrace - however this seems to be tied to using the profiler).

I guess my question is - am I doing something wrong with either my embedding or thread handling?

Any advice on helping to understand and resolve this would be greatly appreciated.

Many thanks

Ron