Minor improvement to multi-threaded support.

2008-05-21  David Smith  <dsmith@redhat.com>

        * tapsets.cxx (utrace_derived_probe_group::emit_module_decls):
        Added new 'event_flag' parameter to task_finder callback.  Only
        calls probe handlers if we received the correct event.

2008-05-21  David Smith  <dsmith@redhat.com>

        * task_finder.c (__stp_utrace_attach_match_filename): Added
        event_flag parameter of event to pass to callback.
        (__stp_utrace_task_finder_target_death): Ditto.
        (__stp_utrace_task_finder_report_clone): Calls
        __stp_utrace_attach_match_filename() with new argument.
        (__stp_utrace_task_finder_report_exec): Ditto.
        (stap_start_task_finder): Calls callback with an invalid
        event_flag since this callback call isn't related to an event.

4 files changed, 44 insertions, 10 deletions

diff --git a/ChangeLog b/ChangeLog
index cb786d0e..806fcfa3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -25,6 +25,12 @@
 	* tapset/ppc64/registers.stp: Support powerpc register + arg lookup
 	* stapfuncs.5.in: Add powerpc bits; indicate scope of uarg_* access
 
+2008-05-21  David Smith  <dsmith@redhat.com>:ChangeLog
+
+	* tapsets.cxx (utrace_derived_probe_group::emit_module_decls):
+	Added new 'event_flag' parameter to task_finder callback.  Only
+	calls probe handlers if we received the correct event.
+
 2008-05-20  Frank Ch. Eigler  <fche@elastic.org>
 
 	PR 6538
diff --git a/runtime/ChangeLog b/runtime/ChangeLog
index 3d506a18..0b7559b9 100644
--- a/runtime/ChangeLog
+++ b/runtime/ChangeLog
@@ -6,6 +6,17 @@
 	facilites (controlled by autoconf).
 	* autoconf-probe-kernel.c: test for above.
 
+2008-05-21  David Smith  <dsmith@redhat.com>
+
+	* task_finder.c (__stp_utrace_attach_match_filename): Added
+	event_flag parameter of event to pass to callback.
+	(__stp_utrace_task_finder_target_death): Ditto.
+	(__stp_utrace_task_finder_report_clone): Calls
+	__stp_utrace_attach_match_filename() with new argument.
+	(__stp_utrace_task_finder_report_exec): Ditto.
+	(stap_start_task_finder): Calls callback with an invalid
+	event_flag since this callback call isn't related to an event.
+
 2008-05-16  David Smith  <dsmith@redhat.com>
 
 	PR 6499.
diff --git a/runtime/task_finder.c b/runtime/task_finder.c
index e78caab6..a8de13d0 100644
--- a/runtime/task_finder.c
+++ b/runtime/task_finder.c
@@ -13,6 +13,7 @@ atomic_t __stp_task_finder_state = ATOMIC_INIT(__STP_TF_STARTING);
 
 typedef int (*stap_task_finder_callback)(struct task_struct *tsk,
 					 int register_p,
+					 unsigned long event_flag,
 					 struct stap_task_finder_target *tgt);
 
 struct stap_task_finder_target {
@@ -237,7 +238,8 @@ __stp_utrace_attach(struct task_struct *tsk,
 
 static inline void
 __stp_utrace_attach_match_filename(struct task_struct *tsk,
-				   const char * const filename)
+				   const char * const filename,
+				   unsigned long event_flag)
 {
 	size_t filelen;
 	struct list_head *tgt_node;
@@ -270,9 +272,10 @@ __stp_utrace_attach_match_filename(struct task_struct *tsk,
 				continue;
 
 			if (cb_tgt->callback != NULL) {
-				int rc = cb_tgt->callback(tsk, 1, cb_tgt);
+				int rc = cb_tgt->callback(tsk, 1, event_flag,
+							  cb_tgt);
 				if (rc != 0) {
-					_stp_error("exec callback for %d failed: %d",
+					_stp_error("callback for %d failed: %d",
 						   (int)tsk->pid, rc);
 					break;
 				}
@@ -332,7 +335,8 @@ __stp_utrace_task_finder_report_clone(struct utrace_attached_engine *engine,
 			   rc, (int)child->pid);
 	}
 	else {
-		__stp_utrace_attach_match_filename(child, mmpath);
+		__stp_utrace_attach_match_filename(child, mmpath,
+						   UTRACE_EVENT(CLONE));
 	}
 
 	_stp_kfree(mmpath_buf);
@@ -357,7 +361,8 @@ __stp_utrace_task_finder_report_exec(struct utrace_attached_engine *engine,
 	if (bprm->filename == NULL)
 		return UTRACE_ACTION_RESUME;
 
-	__stp_utrace_attach_match_filename(tsk, bprm->filename);
+	__stp_utrace_attach_match_filename(tsk, bprm->filename,
+					   UTRACE_EVENT(EXEC));
 
 	return UTRACE_ACTION_RESUME;
 }
@@ -392,7 +397,7 @@ __stp_utrace_task_finder_target_death(struct utrace_attached_engine *engine,
 		int rc;
 
 		// Call the callback
-		rc = tgt->callback(tsk, 0, tgt);
+		rc = tgt->callback(tsk, 0, UTRACE_EVENT(DEATH), tgt);
 		if (rc != 0) {
 			_stp_error("death callback for %d failed: %d",
 				   (int)tsk->pid, rc);
@@ -485,8 +490,17 @@ stap_start_task_finder(void)
 				if (cb_tgt == NULL || cb_tgt->callback == NULL)
 					continue;
 					
-				// Call the callback.
-				rc = cb_tgt->callback(tsk, 1, cb_tgt);
+				// Call the callback.  Notice we're
+				// not passing a valid event_flag
+				// here.  That's OK, for 2 reasons.
+				// (1) We're not in the
+				// STAP_SESSION_RUNNING state yet, so
+				// probes won't get called anyway.
+				// (2) There really isn't an event
+				// associated with this callback call,
+				// we just want to let the caller
+				// attach to the thread.
+				rc = cb_tgt->callback(tsk, 1, 0, cb_tgt);
 				if (rc != 0) {
 					_stp_error("attach callback for %d failed: %d",
 						   (int)tsk->pid, rc);
diff --git a/tapsets.cxx b/tapsets.cxx
index 8203c568..c1bc88b0 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -5487,7 +5487,7 @@ utrace_derived_probe_group::emit_module_decls (systemtap_session& s)
 
   // Output task finder callback routine that gets called for all
   // utrace probe types.
-  s.op->newline() << "static int _stp_utrace_probe_cb(struct task_struct *tsk, int register_p, struct stap_task_finder_target *tgt) {";
+  s.op->newline() << "static int _stp_utrace_probe_cb(struct task_struct *tsk, int register_p, unsigned long event_flag, struct stap_task_finder_target *tgt) {";
   s.op->indent(1);
   s.op->newline() << "int rc = 0;";
   s.op->newline() << "struct stap_utrace_probe *p = container_of(tgt, struct stap_utrace_probe, tgt);";
@@ -5508,7 +5508,10 @@ utrace_derived_probe_group::emit_module_decls (systemtap_session& s)
     {
       s.op->newline() << "case UTRACE_EVENT(EXEC):";
       s.op->indent(1);
+      s.op->newline() << "if (event_flag == UTRACE_EVENT(EXEC)) {";
+      s.op->indent(1);
       s.op->newline() << "stap_utrace_probe_handler(tsk, p);";
+      s.op->newline(-1) << "}";
       s.op->newline() << "break;";
       s.op->indent(-1);
     }
@@ -5561,7 +5564,7 @@ utrace_derived_probe_group::emit_module_decls (systemtap_session& s)
   // For death probes, go ahead and call the probe directly.
   if (flags_seen[UDPF_DEATH])
     {
-      s.op->newline() << "if (p->flags == UTRACE_EVENT(DEATH)) {";
+      s.op->newline() << "if (p->flags == UTRACE_EVENT(DEATH) && event_flag == UTRACE_EVENT(DEATH)) {";
       s.op->indent(1);
       s.op->newline() << "stap_utrace_probe_handler(tsk, p);";
       s.op->newline(-1) << "}";