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

[Subrata Modak <subrata@linux.vnet.ibm.com>]

On Tue, 2009-09-08 at 17:15 +0800, liubo wrote: 
> 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>

This fails to apply. Needs to be re-created against the latest LTP
snapshots from CVS:

patching file testcases/kernel/controllers/cpuctl/cpuctl_def_task01.c
Hunk #1 FAILED at 82.
1 out of 1 hunk FAILED -- saving rejects to file
testcases/kernel/controllers/cpuctl/cpuctl_def_task01.c.rej
patching file testcases/kernel/controllers/cpuctl/cpuctl_def_task02.c
Hunk #1 succeeded at 79 with fuzz 2.
patching file testcases/kernel/controllers/cpuctl/cpuctl_def_task03.c
Hunk #1 succeeded at 79 with fuzz 2.
patching file testcases/kernel/controllers/cpuctl/cpuctl_def_task04.c
Hunk #1 succeeded at 78 with fuzz 2.
patching file testcases/kernel/controllers/cpuctl/cpuctl_test01.c
Hunk #1 FAILED at 80.
1 out of 1 hunk FAILED -- saving rejects to file
testcases/kernel/controllers/cpuctl/cpuctl_test01.c.rej
patching file testcases/kernel/controllers/cpuctl/cpuctl_test02.c
Hunk #1 FAILED at 80.
1 out of 1 hunk FAILED -- saving rejects to file
testcases/kernel/controllers/cpuctl/cpuctl_test02.c.rej
patching file testcases/kernel/controllers/cpuctl/cpuctl_test03.c
Hunk #1 succeeded at 79 with fuzz 2.
patching file testcases/kernel/controllers/cpuctl/cpuctl_test04.c
Hunk #1 succeeded at 79 with fuzz 2.
patching file
testcases/kernel/controllers/libcontrollers/libcontrollers.h
Hunk #1 succeeded at 48 with fuzz 2.

Regards--
Subrata

> ---
> diff --git a/testcases/kernel/controllers/cpuctl/cpuctl_def_task01.c 
> b/testcases/kernel/controllers/cpuctl/cpuctl_def_task01.c
> index 00a25bc..1fb398a 100644
> --- a/testcases/kernel/controllers/cpuctl/cpuctl_def_task01.c
> +++ b/testcases/kernel/controllers/cpuctl/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/testcases/kernel/controllers/cpuctl/cpuctl_def_task02.c 
> b/testcases/kernel/controllers/cpuctl/cpuctl_def_task02.c
> index 1bfa187..56ddacc 100644
> --- a/testcases/kernel/controllers/cpuctl/cpuctl_def_task02.c
> +++ b/testcases/kernel/controllers/cpuctl/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/testcases/kernel/controllers/cpuctl/cpuctl_def_task03.c 
> b/testcases/kernel/controllers/cpuctl/cpuctl_def_task03.c
> index e4ce3ad..4f3ddc1 100644
> --- a/testcases/kernel/controllers/cpuctl/cpuctl_def_task03.c
> +++ b/testcases/kernel/controllers/cpuctl/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/testcases/kernel/controllers/cpuctl/cpuctl_def_task04.c 
> b/testcases/kernel/controllers/cpuctl/cpuctl_def_task04.c
> index 15e2b5f..7f184c8 100644
> --- a/testcases/kernel/controllers/cpuctl/cpuctl_def_task04.c
> +++ b/testcases/kernel/controllers/cpuctl/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/testcases/kernel/controllers/cpuctl/cpuctl_test01.c 
> b/testcases/kernel/controllers/cpuctl/cpuctl_test01.c
> index ab0a4c9..7d7cc48 100644
> --- a/testcases/kernel/controllers/cpuctl/cpuctl_test01.c
> +++ b/testcases/kernel/controllers/cpuctl/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/testcases/kernel/controllers/cpuctl/cpuctl_test02.c 
> b/testcases/kernel/controllers/cpuctl/cpuctl_test02.c
> index 801716d..153a293 100644
> --- a/testcases/kernel/controllers/cpuctl/cpuctl_test02.c
> +++ b/testcases/kernel/controllers/cpuctl/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/testcases/kernel/controllers/cpuctl/cpuctl_test03.c 
> b/testcases/kernel/controllers/cpuctl/cpuctl_test03.c
> index c4b9978..c21b69c 100644
> --- a/testcases/kernel/controllers/cpuctl/cpuctl_test03.c
> +++ b/testcases/kernel/controllers/cpuctl/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/testcases/kernel/controllers/cpuctl/cpuctl_test04.c 
> b/testcases/kernel/controllers/cpuctl/cpuctl_test04.c
> index b0a2329..ed00b0d 100644
> --- a/testcases/kernel/controllers/cpuctl/cpuctl_test04.c
> +++ b/testcases/kernel/controllers/cpuctl/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/testcases/kernel/controllers/libcontrollers/libcontrollers.h 
> b/testcases/kernel/controllers/libcontrollers/libcontrollers.h
> index 777ff67..e6ab6a0 100644
> --- a/testcases/kernel/controllers/libcontrollers/libcontrollers.h
> +++ b/testcases/kernel/controllers/libcontrollers/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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