base: distinct TRACED from ATTACHED trace subjects

This patch makes the trace-subject state as reflected to the trace
monitor more accurate.

Until now, a subject could be in UNTRACED or TRACED state. In reality,
however, there exists an intermediate state after the trace monitor
called 'trace' for the subject but before the subject locally activated
the tracing (done when passing a trace point). This intermediate state
was reflected as UNTRACED. Consequently, threads that never pass a trace
point (e.g., just waiting for I/O) would remain to appear as UNTRACED
even after enabling its tracing by the trace monitor. This is confusing.

This patch replaces the former UNTRACED and TRACED states by three
distinct states:

  UNATTACHED  prior any call of 'trace'
  ATTACHED    after a trace monitor called 'trace'
              but before the tracing is active
  TRACE       tracing is active

Fixes #4447
This commit is contained in:
Norman Feske 2022-03-11 14:06:16 +01:00 committed by Christian Helmuth
parent f3984ba5a9
commit be0a1742ac
3 changed files with 30 additions and 37 deletions

View File

@ -107,17 +107,18 @@ class Genode::Trace::Subject_info
{
public:
enum State { INVALID, UNTRACED, TRACED, FOREIGN, ERROR, DEAD };
enum State { INVALID, UNATTACHED, ATTACHED, TRACED, FOREIGN, ERROR, DEAD };
static char const *state_name(State state)
{
switch (state) {
case INVALID: return "INVALID";
case UNTRACED: return "UNTRACED";
case TRACED: return "TRACED";
case FOREIGN: return "FOREIGN";
case ERROR: return "ERROR";
case DEAD: return "DEAD";
case INVALID: return "INVALID";
case UNATTACHED: return "UNATTACHED";
case ATTACHED: return "ATTACHED";
case TRACED: return "TRACED";
case FOREIGN: return "FOREIGN";
case ERROR: return "ERROR";
case DEAD: return "DEAD";
}
return "INVALID";
}

View File

@ -156,24 +156,29 @@ class Genode::Trace::Subject
if (!source.valid())
return Subject_info::DEAD;
if (source->enabled())
return source->owned_by(*this) ? Subject_info::TRACED
: Subject_info::FOREIGN;
if (source->error())
return Subject_info::ERROR;
return Subject_info::UNTRACED;
if (source->enabled() && !source->owned_by(*this))
return Subject_info::FOREIGN;
if (source->owned_by(*this))
return source->enabled() ? Subject_info::TRACED
: Subject_info::ATTACHED;
return Subject_info::UNATTACHED;
}
void _traceable_or_throw()
{
switch(_state()) {
case Subject_info::DEAD : throw Source_is_dead();
case Subject_info::FOREIGN : throw Traced_by_other_session();
case Subject_info::ERROR : throw Source_is_dead();
case Subject_info::INVALID : throw Nonexistent_subject();
case Subject_info::UNTRACED: return;
case Subject_info::TRACED : return;
case Subject_info::DEAD : throw Source_is_dead();
case Subject_info::FOREIGN : throw Traced_by_other_session();
case Subject_info::ERROR : throw Source_is_dead();
case Subject_info::INVALID : throw Nonexistent_subject();
case Subject_info::UNATTACHED : return;
case Subject_info::ATTACHED : return;
case Subject_info::TRACED : return;
}
}

View File

@ -202,19 +202,6 @@ struct Test_tracing
Rom_dataspace_capability policy_module_rom_ds { };
char const *state_name(Trace::Subject_info::State state)
{
switch (state) {
case Trace::Subject_info::INVALID: return "INVALID";
case Trace::Subject_info::UNTRACED: return "UNTRACED";
case Trace::Subject_info::TRACED: return "TRACED";
case Trace::Subject_info::FOREIGN: return "FOREIGN";
case Trace::Subject_info::ERROR: return "ERROR";
case Trace::Subject_info::DEAD: return "DEAD";
}
return "undefined";
}
struct Failed : Genode::Exception { };
Test_tracing(Env &env) : env(env)
@ -262,7 +249,7 @@ struct Test_tracing
log("ID:", id.id, " "
"label:\"", info.session_label(), "\" "
"name:\"", info.thread_name(), "\" "
"state:", state_name(info.state()), " "
"state:", Trace::Subject_info::state_name(info.state()), " "
"policy:", info.policy_id().id, " "
"thread context time:", info.execution_time().thread_context, " "
"scheduling context time:", info.execution_time().scheduling_context, " ",
@ -272,20 +259,20 @@ struct Test_tracing
trace.for_each_subject_info(print_info);
auto check_untraced = [this] (Trace::Subject_id id, Trace::Subject_info info) {
auto check_unattached = [this] (Trace::Subject_id id, Trace::Subject_info info) {
if (info.state() != Trace::Subject_info::UNTRACED)
error("Subject ", id.id, " is not UNTRACED");
if (info.state() != Trace::Subject_info::UNATTACHED)
error("Subject ", id.id, " is not UNATTACHED");
};
trace.for_each_subject_info(check_untraced);
trace.for_each_subject_info(check_unattached);
/* enable tracing for test-thread */
auto enable_tracing = [this, &env] (Trace::Subject_id id,
Trace::Subject_info info) {
if ( info.session_label() != policy_label
|| info.thread_name() != policy_thread) {
if (info.session_label() != policy_label
|| info.thread_name() != policy_thread) {
return;
}