From 8d59b39f96b89eb055d77d422a923c499d2a5fca Mon Sep 17 00:00:00 2001
From: "Frank Ch. Eigler" <fche@elastic.org>
Date: Wed, 26 Nov 2008 13:59:53 -0500
Subject: [PATCH] safety: add paranoid call to synchronize_sched() during
 shutdown process

---
 ChangeLog                            | 6 ++++++
 buildrun.cxx                         | 2 ++
 runtime/ChangeLog                    | 4 ++++
 runtime/autoconf-synchronize-sched.c | 6 ++++++
 translate.cxx                        | 6 ++++++
 5 files changed, 24 insertions(+)
 create mode 100644 runtime/autoconf-synchronize-sched.c

diff --git a/ChangeLog b/ChangeLog
index fd3860e60..8572035bf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2008-11-26  Frank Ch. Eigler  <fche@elastic.org>
+
+	* translate.cxx (emit_module_exit): Call synchronize_sched during
+	module shutdown if it's available.
+	* buildrun.cxx (compile_pass): Test for it.
+
 2008-11-25  Frank Ch. Eigler  <fche@elastic.org>
 
 	PR 7046.
diff --git a/buildrun.cxx b/buildrun.cxx
index c23a47479..9eeab4baf 100644
--- a/buildrun.cxx
+++ b/buildrun.cxx
@@ -112,6 +112,8 @@ compile_pass (systemtap_session& s)
   o << module_cflags << " += $(call stap_check_build, $(SYSTEMTAP_RUNTIME)/autoconf-uaccess.c, -DSTAPCONF_LINUX_UACCESS_H,)" << endl;
   o << module_cflags << " += $(call stap_check_build, $(SYSTEMTAP_RUNTIME)/autoconf-oneachcpu-retry.c, -DSTAPCONF_ONEACHCPU_RETRY,)" << endl;
   o << module_cflags << " += $(call stap_check_build, $(SYSTEMTAP_RUNTIME)/autoconf-dpath-path.c, -DSTAPCONF_DPATH_PATH,)" << endl;
+  o << module_cflags << " += $(call stap_check_build, $(SYSTEMTAP_RUNTIME)/autoconf-synchronize-sched.c, -DSTAPCONF_SYNCHRONIZE_SCHED,)" << endl;
+
 #if 0
   /* NB: For now, the performance hit of probe_kernel_read/write (vs. our
    * homegrown safe-access functions) is deemed undesireable, so we'll skip
diff --git a/runtime/ChangeLog b/runtime/ChangeLog
index 91a932c47..f3c5f2e3c 100644
--- a/runtime/ChangeLog
+++ b/runtime/ChangeLog
@@ -1,3 +1,7 @@
+2008-11-26  Frank Ch. Eigler  <fche@elastic.org>
+
+	* autoconf-synchronize-sched.c: New file.
+
 2008-11-25  Frank Ch. Eigler  <fche@elastic.org>
 
 	PR 7046.
diff --git a/runtime/autoconf-synchronize-sched.c b/runtime/autoconf-synchronize-sched.c
new file mode 100644
index 000000000..0291092e2
--- /dev/null
+++ b/runtime/autoconf-synchronize-sched.c
@@ -0,0 +1,6 @@
+#include <linux/sched.h>
+
+void foo (void)
+{
+  synchronize_sched ();
+}
diff --git a/translate.cxx b/translate.cxx
index 1cf7361e8..41a424ed6 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -1287,6 +1287,11 @@ c_unparser::emit_module_exit ()
   o->newline () << "yield ();"; // aka schedule() and then some 
   o->newline(-2) << "} while (holdon);";
 
+  // 
+  o->newline() << "#ifdef STAPCONF_SYNCHRONIZE_SCHED";
+  o->newline() << "synchronize_sched();";
+  o->newline() << "#endif";
+
   // XXX: might like to have an escape hatch, in case some probe is
   // genuinely stuck somehow
 
@@ -4860,6 +4865,7 @@ translate_pass (systemtap_session& s)
       s.op->newline() << "#include \"stat.c\"";
       s.op->newline() << "#include <linux/string.h>";
       s.op->newline() << "#include <linux/timer.h>";
+      s.op->newline() << "#include <linux/sched.h>";
       s.op->newline() << "#include <linux/delay.h>";
       s.op->newline() << "#include <linux/profile.h>";
       s.op->newline() << "#include <linux/random.h>";
-- 
2.43.5