[LTP] [PATCH] cpuctl of controllers: fix the bug of while loop

[liubo <liubo-fnst@cn.fujitsu.com>]

When running the ltp tool by "./runltp -f controllers",
I found "while" loop cannot stop in following files of
cpuctl test.

File list:
cpuctl_def_task01.c
cpuctl_def_task02.c
cpuctl_def_task03.c
cpuctl_def_task04.c
cpuctl_test01.c
cpuctl_test02.c
cpuctl_test03.c
cpuctl_test04.c

Key code:
timer_expired=0;
while(!timer_expired)
	f=sqrt(f*f);

Reason:
During the compilation of these files, gcc's O2 mechanism
  causes the change of variable "timer_expired" to be omitted,
hence the loop, "while(!timer_expired) f=sqrt(f*f);" cannot
get out from itself.

Change the type of "timer_expired" from "int" to "volatile int"
to fix this bug.

By the way, it is necessary to modify the file,
ltp-full-xxxxxxxx/testcases/kernel/controllers/libcontrollers/
libcontrollers.h for compilation.


Signed-off-by: Miao Xie<miaox@cn.fujitsu.com>
Signed-off-by: Liu Bo<liubo-fnst@cn.fujitsu.com>
---
diff --git a/cpuctl_def_task01.c b/cpuctl_def_task01.c
index 00a25bc..1fb398a 100644
--- a/cpuctl_def_task01.c
+++ b/cpuctl_def_task01.c
@@ -82,7 +82,7 @@ extern void cleanup()
         kill(scriptpid, SIGUSR1);/* Inform the shell to do cleanup*/
         tst_exit();             /* Report exit status*/
  }
-int timer_expired = 0;
+volatile int timer_expired = 0;

  int main(int argc, char *argv[])
  {
diff --git a/cpuctl_def_task02.c b/cpuctl_def_task02.c
index 1bfa187..56ddacc 100644
--- a/cpuctl_def_task02.c
+++ b/cpuctl_def_task02.c
@@ -79,7 +79,7 @@ cleanup()
         tst_exit();             /* Report exit status*/
  }

-int timer_expired = 0;
+volatile int timer_expired = 0;

  int main(int argc, char *argv[])
  {
diff --git a/cpuctl_def_task03.c b/cpuctl_def_task03.c
index e4ce3ad..4f3ddc1 100644
--- a/cpuctl_def_task03.c
+++ b/cpuctl_def_task03.c
@@ -79,7 +79,7 @@ cleanup()
         tst_exit();               /* Report exit status*/
  }

-int timer_expired = 0;
+volatile int timer_expired = 0;

  int main(int argc, char *argv[])
  {
diff --git a/cpuctl_def_task04.c b/cpuctl_def_task04.c
index 15e2b5f..7f184c8 100644
--- a/cpuctl_def_task04.c
+++ b/cpuctl_def_task04.c
@@ -78,7 +78,7 @@ cleanup()
         tst_exit();               /* Report exit status*/
  }

-int timer_expired = 0;
+volatile int timer_expired = 0;

  int main(int argc, char *argv[])
  {
diff --git a/cpuctl_test01.c b/cpuctl_test01.c
index ab0a4c9..7d7cc48 100644
--- a/cpuctl_test01.c
+++ b/cpuctl_test01.c
@@ -80,7 +80,7 @@ cleanup()
         kill (scriptpid, SIGUSR1);/* Inform the shell to do cleanup*/
         tst_exit ();            /* Report exit status*/
  }
-int timer_expired = 0;
+volatile int timer_expired = 0;

  int main(int argc, char* argv[])
  {
diff --git a/cpuctl_test02.c b/cpuctl_test02.c
index 801716d..153a293 100644
--- a/cpuctl_test02.c
+++ b/cpuctl_test02.c
@@ -80,7 +80,7 @@ cleanup()
  }

  int migrate_task ();
-int timer_expired = 0;
+volatile int timer_expired = 0;

  int main(int argc, char* argv[])
  {
diff --git a/cpuctl_test03.c b/cpuctl_test03.c
index c4b9978..c21b69c 100644
--- a/cpuctl_test03.c
+++ b/cpuctl_test03.c
@@ -79,7 +79,7 @@ cleanup()
         tst_exit ();              /* Report exit status*/
  }

-int timer_expired = 0;
+volatile int timer_expired = 0;

  int main(int argc, char* argv[])
  {
diff --git a/cpuctl_test04.c b/cpuctl_test04.c
index b0a2329..ed00b0d 100644
--- a/cpuctl_test04.c
+++ b/cpuctl_test04.c
@@ -79,7 +79,7 @@ cleanup()
         tst_exit ();              /* Report exit status*/
  }

-int timer_expired = 0;
+volatile int timer_expired = 0;

  int main(int argc, char* argv[])
  {
diff --git a/libcontrollers.h b/libcontrollers.h
index 777ff67..e6ab6a0 100644
--- a/libcontrollers.h
+++ b/libcontrollers.h
@@ -48,7 +48,8 @@ char fullpath[PATH_MAX];
  char fullpath[1024]; /* Guess */
  #endif

-int FLAG, timer_expired;
+int FLAG;
+volatile int timer_expired;

  int retval;






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