Messages in this thread Patch in this message | | | Date | Thu, 9 Aug 2012 19:18:02 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [RFC 5/5] uprobes: add global breakpoints |
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* Oleg Nesterov | 2012-08-08 15:14:57 [+0200]:
>> What I miss right now is an interface to tell the user/gdb that there is a >> program that hit a global breakpoint and is waiting for further instructions. >> A "tail -f trace" does not work and may contain also a lot of other >> informations. I've been thinking about a poll()able file which returns pids of >> tasks which are put on hold. Other suggestions? > >Honestly, I am not sure this is that useful...
How would you notify gdb that there is a new task that hit a breakpoint? Or learn yourself?
>OK, I'll try to read this patch later. But, at first glance, Thank you.
>> @@ -286,8 +286,10 @@ static int ptrace_attach(struct task_struct *task, long request, >> __ptrace_link(task, current); >> >> /* SEIZE doesn't trap tracee on attach */ >> - if (!seize) >> + if (!seize) { >> send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); >> + uprobe_wakeup_task(task, 1); >> + } > >Can't understand why uprobe_wakeup_task() depends on !PTRACE_SEIZE
because in the SEIZE case the task isn't halted, it continues to run. Or do you want to use PTRACE_SEIZE for tasks which hit the global breakpoint and you have no interrest in them and want them to continue like nothing happend?
>> + >> + set_current_state(TASK_TRACED); >> + schedule(); >> +} > >Suppose that uprobe_wakeup_task() is called in the WINDOW above. > >OTOH, uprobe_wakeup_task() can race with itself if it is called >twice at the same time, say from uprobes_gp_wakeup_write() and >ptrace_attach(). Okay, I'm going to close the window.
> >Oleg.
Sebastian
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