Re: [Bug uprobes/11672] utrace_report_syscall_exit crash

[Roland McGrath <roland at redhat dot com>]

> This is called from the task finder cleanup code and the utrace probe
> exit code before the module tries to unload. 

>From a quick glance I'm still not really clear on the important question:
what thread is current when calling into this code?

> Busy-waiting is bad, so if there is an alternative that would be nice.
> All we need is that if after a utrace_control UTRACE_DETACH we get an
> -EINPROGRESS that we can wait till we are sure any pending handlers have
> finished and that the detach fully succeeded.

As I said, utrace_barrier is that except that it's a busy-wait if
signal_pending().  The alternative requires changing your model such that
any waiting is via your own synchronization with your ops->release
function.


Thanks,
Roland