I decided to run it from the command line and copy the additional debug messages. Looks like it might be a problem with Moonlight firefox (firefox:5677): GLib-WARNING **: g_set_prgname() called multiple times Attempting to load libmoonloaderxpi Moonlight: Installing signal handlers for crash reporting. Moonlight: Enabling MONO_DEBUG=keep-delegates and MOONLIGHT_ENABLE_CONSOLE=1 ** (firefox:5677): WARNING **: Thread (nil) may have been prematurely finalized ============================================================= Got a SIGSEGV while executing native code. We'll first ask gdb for a stack trace, then try our own stack walking method (usually not as good as gdb, but it can do managed and native stack traces together) ============================================================= Debug info from gdb: Cannot access memory at address 0x8389c089 [Thread debugging using libthread_db enabled] [New Thread 0x97c8b70 (LWP 5727)] [New Thread 0xac2ffb70 (LWP 5726)] [New Thread 0xab5ffb70 (LWP 5725)] [New Thread 0xad3feb70 (LWP 5705)] [New Thread 0xae8feb70 (LWP 5704)] [New Thread 0xb40feb70 (LWP 5703)] [New Thread 0xadbffb70 (LWP 5698)] [New Thread 0xaf0ffb70 (LWP 5693)] [New Thread 0xafaffb70 (LWP 5692)] [New Thread 0xb55ffb70 (LWP 5691)] [New Thread 0xb38fdb70 (LWP 5690)] [New Thread 0xb48ffb70 (LWP 5689)] [New Thread 0xb60fdb70 (LWP 5682)] [New Thread 0xb68feb70 (LWP 5681)] [New Thread 0xb70ffb70 (LWP 5680)] 0x00f9a422 in __kernel_vsyscall () 16 Thread 0xb70ffb70 (LWP 5680) 0x00f9a422 in __kernel_vsyscall () 15 Thread 0xb68feb70 (LWP 5681) 0x00f9a422 in __kernel_vsyscall () 14 Thread 0xb60fdb70 (LWP 5682) 0x00f9a422 in __kernel_vsyscall () 13 Thread 0xb48ffb70 (LWP 5689) 0x00f9a422 in __kernel_vsyscall () 12 Thread 0xb38fdb70 (LWP 5690) 0x00f9a422 in __kernel_vsyscall () 11 Thread 0xb55ffb70 (LWP 5691) 0x00f9a422 in __kernel_vsyscall () 10 Thread 0xafaffb70 (LWP 5692) 0x00f9a422 in __kernel_vsyscall () 9 Thread 0xaf0ffb70 (LWP 5693) 0x00f9a422 in __kernel_vsyscall () 8 Thread 0xadbffb70 (LWP 5698) 0x00f9a422 in __kernel_vsyscall () 7 Thread 0xb40feb70 (LWP 5703) 0x00f9a422 in __kernel_vsyscall () 6 Thread 0xae8feb70 (LWP 5704) 0x00f9a422 in __kernel_vsyscall () 5 Thread 0xad3feb70 (LWP 5705) 0x00f9a422 in __kernel_vsyscall () 4 Thread 0xab5ffb70 (LWP 5725) 0x00f9a422 in __kernel_vsyscall () 3 Thread 0xac2ffb70 (LWP 5726) 0x00f9a422 in __kernel_vsyscall () 2 Thread 0x97c8b70 (LWP 5727) 0x00f9a422 in __kernel_vsyscall () * 1 Thread 0xb77f26e0 (LWP 5677) 0x00f9a422 in __kernel_vsyscall () Thread 16 (Thread 0xb70ffb70 (LWP 5680)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00833142 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00ccda4e in ?? () from /usr/lib/libnspr4.so #3 0x00cce834 in PR_WaitCondVar () from /usr/lib/libnspr4.so #4 0x0115e22c in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #6 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #7 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 15 (Thread 0xb68feb70 (LWP 5681)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x0041dc96 in poll () from /lib/tls/i686/cmov/libc.so.6 #2 0x00cd05fc in ?? () from /usr/lib/libnspr4.so #3 0x011bf589 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #4 0x011bfa8a in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x011bfc9d in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #6 0x01970fba in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #7 0x0194175f in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #8 0x011bf788 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #9 0x01971015 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #10 0x0194175f in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #11 0x01971717 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #12 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #13 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #14 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 14 (Thread 0xb60fdb70 (LWP 5682)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00833142 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00ccda4e in ?? () from /usr/lib/libnspr4.so #3 0x00cce834 in PR_WaitCondVar () from /usr/lib/libnspr4.so #4 0x0197474a in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x01971015 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #6 0x0194175f in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #7 0x01971717 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #8 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #9 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #10 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 13 (Thread 0xb48ffb70 (LWP 5689)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00832e15 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00cce8cb in PR_WaitCondVar () from /usr/lib/libnspr4.so #3 0x017abff6 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #4 0x017ab906 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #6 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #7 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 12 (Thread 0xb38fdb70 (LWP 5690)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00832e15 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00cce8cb in PR_WaitCondVar () from /usr/lib/libnspr4.so #3 0x017ad014 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #4 0x017ab906 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #6 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #7 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 11 (Thread 0xb55ffb70 (LWP 5691)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00832e15 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00cce8cb in PR_WaitCondVar () from /usr/lib/libnspr4.so #3 0x00cce937 in PR_Wait () from /usr/lib/libnspr4.so #4 0x019701e3 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x01970fed in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #6 0x0194175f in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #7 0x01971717 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #8 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #9 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #10 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 10 (Thread 0xafaffb70 (LWP 5692)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00832e15 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00cce8cb in PR_WaitCondVar () from /usr/lib/libnspr4.so #3 0x00cce937 in PR_Wait () from /usr/lib/libnspr4.so #4 0x019701e3 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x01970fed in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #6 0x0194175f in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #7 0x01971717 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #8 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #9 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #10 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 9 (Thread 0xaf0ffb70 (LWP 5693)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00833142 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00ccda4e in ?? () from /usr/lib/libnspr4.so #3 0x00cce834 in PR_WaitCondVar () from /usr/lib/libnspr4.so #4 0x011c87e9 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x011c91f4 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #6 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #7 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #8 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 8 (Thread 0xadbffb70 (LWP 5698)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00833142 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00ccda4e in ?? () from /usr/lib/libnspr4.so #3 0x00cce834 in PR_WaitCondVar () from /usr/lib/libnspr4.so #4 0x00cce937 in PR_Wait () from /usr/lib/libnspr4.so #5 0x01972cac in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #6 0x01971015 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #7 0x0194175f in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #8 0x01971717 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #9 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #10 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #11 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 7 (Thread 0xb40feb70 (LWP 5703)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00833142 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00ccda4e in ?? () from /usr/lib/libnspr4.so #3 0x00cce834 in PR_WaitCondVar () from /usr/lib/libnspr4.so #4 0x011c87e9 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x011c91f4 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #6 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #7 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #8 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 6 (Thread 0xae8feb70 (LWP 5704)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00833142 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00ccda4e in ?? () from /usr/lib/libnspr4.so #3 0x00cce834 in PR_WaitCondVar () from /usr/lib/libnspr4.so #4 0x011c87e9 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x011c91f4 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #6 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #7 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #8 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 5 (Thread 0xad3feb70 (LWP 5705)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00833142 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x00ccda4e in ?? () from /usr/lib/libnspr4.so #3 0x00cce834 in PR_WaitCondVar () from /usr/lib/libnspr4.so #4 0x011c87e9 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #5 0x011c91f4 in ?? () from /usr/lib/xulrunner-1.9.1.8/libxul.so #6 0x00cd4c07 in ?? () from /usr/lib/libnspr4.so #7 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #8 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 4 (Thread 0xab5ffb70 (LWP 5725)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00832e15 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0xb169879f in ?? () from /usr/lib/adobe-flashplugin/libflashplayer.so #3 0xb17cb7ff in ?? () from /usr/lib/adobe-flashplugin/libflashplayer.so #4 0xb1698c5d in ?? () from /usr/lib/adobe-flashplugin/libflashplayer.so #5 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #6 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 3 (Thread 0xac2ffb70 (LWP 5726)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00832e15 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0xb169879f in ?? () from /usr/lib/adobe-flashplugin/libflashplayer.so #3 0xb17cb7ff in ?? () from /usr/lib/adobe-flashplugin/libflashplayer.so #4 0xb1698c5d in ?? () from /usr/lib/adobe-flashplugin/libflashplayer.so #5 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #6 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 2 (Thread 0x97c8b70 (LWP 5727)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00836466 in nanosleep () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x02777388 in collection_thread (unused=0x0) at collection.c:34 #3 0x0082e80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #4 0x0042b8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 1 (Thread 0xb77f26e0 (LWP 5677)): #0 0x00f9a422 in __kernel_vsyscall () #1 0x00835c8b in read () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x076ede1d in print_gdb_trace () at debug.cpp:709 #3 0x076ef463 in moonlight_handle_native_sigsegv (signal=11) at debug.cpp:762 #4 0x02698db5 in mono_chain_signal (_dummy=11, info=0xb7203c8c, context=0xb7203d0c) at mini-posix.c:133 #5 0x025d6093 in mono_sigsegv_signal_handler (_dummy=11, info=0xb7203c8c, context=0xb7203d0c) at mini.c:4833 #6 #7 0x7fffffff in ?? () #8 0x000090a8 in ?? () Debug info from libmoon: ** (firefox:5677): WARNING **: Thread (nil) may have been prematurely finalized /