[ltt-dev] lttv core

[Mathieu Desnoyers]

* Andy Howell (AndyHowell at raitechnology.com) wrote:
> Hello,
>
> 	I have a trace that is causing problems. The gui comes up ok, but when I 
> zoom in, it dies with:
>
> ** (lttv.real:32675): CRITICAL **: unknown state : (null)
> **
> ** ERROR:(eventhooks.c:273):prepare_s_e_line: assertion failed: (FALSE)
>
> In the gdb I see the following for "process", followed by the stack 
> trace. "process" is optimized out in prepare-s_e_line, but I see the its 
> value in draw_closure.
>
>  print *process
> $5 = {pid = 3571, tgid = 3571, ppid = 1, creation_time = {tv_sec = 33074, 
> tv_nsec = 156251541}, insertion_time = {tv_sec = 33074, tv_nsec = 
> 156251541}, name = 3934, brand = 62, pid_time = 3936, execution_stack = 
> 0x201c620, state = 0x9bdf4d0, cpu = 1, usertrace = 0x0, user_stack = 
> 0x1f32c20, current_function = 0, type = 78, target_pid = 0, free_events = 
> 0}
> (gdb) print *process->state
> $6 = {t = 65, n = 70, entry = {tv_sec = 33074, tv_nsec = 191892096}, 
> change = {tv_sec = 33074, tv_nsec = 191892096}, cum_cpu_time = {tv_sec = 
> 0, tv_nsec = 0}, s = 0}

Hrm, normally lttv should handle missing data. So it's now a
showstopper, as we figured out that there were lots of missing events in
your trace, but it would be good to find out how "s" got a value of 0.
Normally, when unset ("unknown"), it should be set to
LTTV_STATE_UNNAMED.

  See es->s = LTTV_STATE_UNNAMED  in lttv/lttv/state.c.

I fear that the sequence including missing events you faced caused a
thread stack to contain uninitialized information.

Mathieu


>
>
> #0  prepare_s_e_line (process=<value optimized out>) at eventhooks.c:273
> #1  0x00007f6e56aa0468 in draw_closure (key=<value optimized out>, 
> value=0x2057970, user_data=<value optimized out>) at eventhooks.c:2481
> #2  0x000000354002945d in g_hash_table_foreach () from /lib64/libglib-2.0.so.0
> #3  0x00007f6e56aa3184 in after_chunk (hook_data=0x97e2f20, 
> call_data=0x1cdbeb0) at eventhooks.c:2622
> #4  0x000000000040c9e7 in lttv_hooks_call (h=0x1dd2ba0, call_data=0x1cdbeb0) at hook.c:272
> #5  0x00007f6e56ec1c39 in execute_events_requests (tab=0x1a88320) at callbacks.c:1558
> #6  0x000000354003744b in g_main_context_dispatch () from /lib64/libglib-2.0.so.0
> #7  0x000000354003ac2d in ?? () from /lib64/libglib-2.0.so.0
> #8  0x000000354003b15d in g_main_loop_run () from /lib64/libglib-2.0.so.0
> #9  0x0000003542983db0 in gtk_main () from /usr/lib64/libgtk-x11-2.0.so.0
> #10 0x00007f6e56ebdb66 in window_creation_hook (hook_data=<value 
> optimized out>, call_data=<value optimized out>) at init_module.c:129
> #11 0x000000000040c9e7 in lttv_hooks_call (h=0x1a54f40, call_data=0x0) at hook.c:272
> #12 0x000000000040b233 in main (argc=15, argv=0x7fffa8353618) at main.c:219
>
> Regards,
>
> 	Andy
>
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-- 
Mathieu Desnoyers
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