(gdb) bt full
#0  0x00007f5093c46e8d in poll () at ../sysdeps/unix/syscall-template.S:84
No locals.
#1  0x00007f5094a9331c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#2  0x00007f5094a936a2 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#3  0x0000000000407e11 in main (argc=1, argv=0x7ffc50f92378) at lightdm.c:1541
        pid_file = <optimized out>
        option_context = <optimized out>
        result = 1
        dir = <optimized out>
        test_mode = 0
        pid_path = 0x42bde6 "/var/run/lightdm.pid"
        log_dir = 0x0
        run_dir = 0x0
        cache_dir = 0x0
        default_log_dir = 0x25a7e00 "run-directory"
        default_run_dir = 0x25a7e20 "cache-directory"
        default_cache_dir = 0x25a7e40 "sessions-directory"
        show_config = 0
        show_version = 0
        link = <optimized out>
        messages = 0x25a8040
        options = {{long_name = 0x42db11 "config", short_name = 99 'c', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x63cba8 <config_path>, 
            description = 0x42be30 "Use configuration file", arg_description = 0x42be47 "FILE"}, {long_name = 0x42be4c "debug", short_name = 100 'd', 
            flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x63cb90 <debug>, description = 0x42be52 "Print debugging messages", arg_description = 0x0}, {
            long_name = 0x42be6b "test-mode", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f92034, 
            description = 0x42b620 "Run as unprivileged user, skipping things that require root access", arg_description = 0x0}, {
            long_name = 0x42be75 "pid-file", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92040, 
            description = 0x42be7e "File to write PID into", arg_description = 0x42be47 "FILE"}, {long_name = 0x42be95 "log-dir", short_name = 0 '\000', 
            flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92048, description = 0x42be9d "Directory to write logs to", 
            arg_description = 0x42beb8 "DIRECTORY"}, {long_name = 0x42bec2 "run-dir", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, 
            arg_data = 0x7ffc50f92050, description = 0x42b668 "Directory to store running state", arg_description = 0x42beb8 "DIRECTORY"}, {
            long_name = 0x42beca "cache-dir", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92058, 
            description = 0x42b690 "Directory to cache information", arg_description = 0x42beb8 "DIRECTORY"}, {long_name = 0x42bed4 "show-config", 
            short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f92038, description = 0x42bee0 "Show combined configuration", 
            arg_description = 0x0}, {long_name = 0x42bf09 "version", short_name = 118 'v', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f9203c, 
            description = 0x42befc "Show release version", arg_description = 0x0}, {long_name = 0x0, short_name = 0 '\000', flags = 0, 
            arg = G_OPTION_ARG_NONE, arg_data = 0x0, description = 0x0, arg_description = 0x0}}
        error = 0x0
(gdb) 
#0  0x00007f5093c46e8d in poll () at ../sysdeps/unix/syscall-template.S:84
No locals.
#1  0x00007f5094a9331c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#2  0x00007f5094a936a2 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#3  0x0000000000407e11 in main (argc=1, argv=0x7ffc50f92378) at lightdm.c:1541
        pid_file = <optimized out>
        option_context = <optimized out>
        result = 1
        dir = <optimized out>
        test_mode = 0
        pid_path = 0x42bde6 "/var/run/lightdm.pid"
        log_dir = 0x0
        run_dir = 0x0
        cache_dir = 0x0
        default_log_dir = 0x25a7e00 "run-directory"
        default_run_dir = 0x25a7e20 "cache-directory"
        default_cache_dir = 0x25a7e40 "sessions-directory"
        show_config = 0
        show_version = 0
        link = <optimized out>
        messages = 0x25a8040
        options = {{long_name = 0x42db11 "config", short_name = 99 'c', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x63cba8 <config_path>, 
            description = 0x42be30 "Use configuration file", arg_description = 0x42be47 "FILE"}, {long_name = 0x42be4c "debug", short_name = 100 'd', 
            flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x63cb90 <debug>, description = 0x42be52 "Print debugging messages", arg_description = 0x0}, {
            long_name = 0x42be6b "test-mode", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f92034, 
            description = 0x42b620 "Run as unprivileged user, skipping things that require root access", arg_description = 0x0}, {
            long_name = 0x42be75 "pid-file", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92040, 
            description = 0x42be7e "File to write PID into", arg_description = 0x42be47 "FILE"}, {long_name = 0x42be95 "log-dir", short_name = 0 '\000', 
            flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92048, description = 0x42be9d "Directory to write logs to", 
            arg_description = 0x42beb8 "DIRECTORY"}, {long_name = 0x42bec2 "run-dir", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, 
            arg_data = 0x7ffc50f92050, description = 0x42b668 "Directory to store running state", arg_description = 0x42beb8 "DIRECTORY"}, {
            long_name = 0x42beca "cache-dir", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92058, 
            description = 0x42b690 "Directory to cache information", arg_description = 0x42beb8 "DIRECTORY"}, {long_name = 0x42bed4 "show-config", 
            short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f92038, description = 0x42bee0 "Show combined configuration", 
            arg_description = 0x0}, {long_name = 0x42bf09 "version", short_name = 118 'v', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f9203c, 
            description = 0x42befc "Show release version", arg_description = 0x0}, {long_name = 0x0, short_name = 0 '\000', flags = 0, 
            arg = G_OPTION_ARG_NONE, arg_data = 0x0, description = 0x0, arg_description = 0x0}}
        error = 0x0
(gdb) 
#0  0x00007f5093c46e8d in poll () at ../sysdeps/unix/syscall-template.S:84
No locals.
#1  0x00007f5094a9331c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#2  0x00007f5094a936a2 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#3  0x0000000000407e11 in main (argc=1, argv=0x7ffc50f92378) at lightdm.c:1541
        pid_file = <optimized out>
        option_context = <optimized out>
        result = 1
        dir = <optimized out>
        test_mode = 0
        pid_path = 0x42bde6 "/var/run/lightdm.pid"
        log_dir = 0x0
        run_dir = 0x0
        cache_dir = 0x0
        default_log_dir = 0x25a7e00 "run-directory"
        default_run_dir = 0x25a7e20 "cache-directory"
        default_cache_dir = 0x25a7e40 "sessions-directory"
        show_config = 0
        show_version = 0
        link = <optimized out>
        messages = 0x25a8040
        options = {{long_name = 0x42db11 "config", short_name = 99 'c', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x63cba8 <config_path>, 
            description = 0x42be30 "Use configuration file", arg_description = 0x42be47 "FILE"}, {long_name = 0x42be4c "debug", short_name = 100 'd', 
            flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x63cb90 <debug>, description = 0x42be52 "Print debugging messages", arg_description = 0x0}, {
            long_name = 0x42be6b "test-mode", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f92034, 
            description = 0x42b620 "Run as unprivileged user, skipping things that require root access", arg_description = 0x0}, {
            long_name = 0x42be75 "pid-file", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92040, 
            description = 0x42be7e "File to write PID into", arg_description = 0x42be47 "FILE"}, {long_name = 0x42be95 "log-dir", short_name = 0 '\000', 
            flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92048, description = 0x42be9d "Directory to write logs to", 
            arg_description = 0x42beb8 "DIRECTORY"}, {long_name = 0x42bec2 "run-dir", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, 
            arg_data = 0x7ffc50f92050, description = 0x42b668 "Directory to store running state", arg_description = 0x42beb8 "DIRECTORY"}, {
            long_name = 0x42beca "cache-dir", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92058, 
            description = 0x42b690 "Directory to cache information", arg_description = 0x42beb8 "DIRECTORY"}, {long_name = 0x42bed4 "show-config", 
            short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f92038, description = 0x42bee0 "Show combined configuration", 
            arg_description = 0x0}, {long_name = 0x42bf09 "version", short_name = 118 'v', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f9203c, 
            description = 0x42befc "Show release version", arg_description = 0x0}, {long_name = 0x0, short_name = 0 '\000', flags = 0, 
            arg = G_OPTION_ARG_NONE, arg_data = 0x0, description = 0x0, arg_description = 0x0}}
        error = 0x0
(gdb) 
#0  0x00007f5093c46e8d in poll () at ../sysdeps/unix/syscall-template.S:84
No locals.
#1  0x00007f5094a9331c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#2  0x00007f5094a936a2 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#3  0x0000000000407e11 in main (argc=1, argv=0x7ffc50f92378) at lightdm.c:1541
        pid_file = <optimized out>
        option_context = <optimized out>
        result = 1
        dir = <optimized out>
        test_mode = 0
        pid_path = 0x42bde6 "/var/run/lightdm.pid"
        log_dir = 0x0
        run_dir = 0x0
        cache_dir = 0x0
        default_log_dir = 0x25a7e00 "run-directory"
        default_run_dir = 0x25a7e20 "cache-directory"
        default_cache_dir = 0x25a7e40 "sessions-directory"
        show_config = 0
        show_version = 0
        link = <optimized out>
        messages = 0x25a8040
        options = {{long_name = 0x42db11 "config", short_name = 99 'c', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x63cba8 <config_path>, 
            description = 0x42be30 "Use configuration file", arg_description = 0x42be47 "FILE"}, {long_name = 0x42be4c "debug", short_name = 100 'd', 
            flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x63cb90 <debug>, description = 0x42be52 "Print debugging messages", arg_description = 0x0}, {
            long_name = 0x42be6b "test-mode", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f92034, 
            description = 0x42b620 "Run as unprivileged user, skipping things that require root access", arg_description = 0x0}, {
            long_name = 0x42be75 "pid-file", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92040, 
            description = 0x42be7e "File to write PID into", arg_description = 0x42be47 "FILE"}, {long_name = 0x42be95 "log-dir", short_name = 0 '\000', 
            flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92048, description = 0x42be9d "Directory to write logs to", 
            arg_description = 0x42beb8 "DIRECTORY"}, {long_name = 0x42bec2 "run-dir", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, 
            arg_data = 0x7ffc50f92050, description = 0x42b668 "Directory to store running state", arg_description = 0x42beb8 "DIRECTORY"}, {
            long_name = 0x42beca "cache-dir", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92058, 
            description = 0x42b690 "Directory to cache information", arg_description = 0x42beb8 "DIRECTORY"}, {long_name = 0x42bed4 "show-config", 
            short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f92038, description = 0x42bee0 "Show combined configuration", 
            arg_description = 0x0}, {long_name = 0x42bf09 "version", short_name = 118 'v', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f9203c, 
            description = 0x42befc "Show release version", arg_description = 0x0}, {long_name = 0x0, short_name = 0 '\000', flags = 0, 
            arg = G_OPTION_ARG_NONE, arg_data = 0x0, description = 0x0, arg_description = 0x0}}
        error = 0x0
(gdb) bt full
#0  0x00007f5093c46e8d in poll () at ../sysdeps/unix/syscall-template.S:84
No locals.
#1  0x00007f5094a9331c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#2  0x00007f5094a936a2 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#3  0x0000000000407e11 in main (argc=1, argv=0x7ffc50f92378) at lightdm.c:1541
        pid_file = <optimized out>
        option_context = <optimized out>
        result = 1
        dir = <optimized out>
        test_mode = 0
        pid_path = 0x42bde6 "/var/run/lightdm.pid"
        log_dir = 0x0
        run_dir = 0x0
        cache_dir = 0x0
        default_log_dir = 0x25a7e00 "run-directory"
        default_run_dir = 0x25a7e20 "cache-directory"
        default_cache_dir = 0x25a7e40 "sessions-directory"
        show_config = 0
        show_version = 0
        link = <optimized out>
        messages = 0x25a8040
        options = {{long_name = 0x42db11 "config", short_name = 99 'c', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x63cba8 <config_path>, 
            description = 0x42be30 "Use configuration file", arg_description = 0x42be47 "FILE"}, {long_name = 0x42be4c "debug", short_name = 100 'd', 
            flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x63cb90 <debug>, description = 0x42be52 "Print debugging messages", arg_description = 0x0}, {
            long_name = 0x42be6b "test-mode", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f92034, 
            description = 0x42b620 "Run as unprivileged user, skipping things that require root access", arg_description = 0x0}, {
            long_name = 0x42be75 "pid-file", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92040, 
            description = 0x42be7e "File to write PID into", arg_description = 0x42be47 "FILE"}, {long_name = 0x42be95 "log-dir", short_name = 0 '\000', 
            flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92048, description = 0x42be9d "Directory to write logs to", 
            arg_description = 0x42beb8 "DIRECTORY"}, {long_name = 0x42bec2 "run-dir", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, 
            arg_data = 0x7ffc50f92050, description = 0x42b668 "Directory to store running state", arg_description = 0x42beb8 "DIRECTORY"}, {
            long_name = 0x42beca "cache-dir", short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_STRING, arg_data = 0x7ffc50f92058, 
            description = 0x42b690 "Directory to cache information", arg_description = 0x42beb8 "DIRECTORY"}, {long_name = 0x42bed4 "show-config", 
            short_name = 0 '\000', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f92038, description = 0x42bee0 "Show combined configuration", 
            arg_description = 0x0}, {long_name = 0x42bf09 "version", short_name = 118 'v', flags = 0, arg = G_OPTION_ARG_NONE, arg_data = 0x7ffc50f9203c, 
            description = 0x42befc "Show release version", arg_description = 0x0}, {long_name = 0x0, short_name = 0 '\000', flags = 0, 
            arg = G_OPTION_ARG_NONE, arg_data = 0x0, description = 0x0, arg_description = 0x0}}
        error = 0x0
(gdb)