Hello,

I would like to share two observations -

1. Is it necessary to initialize  nrcpus = 2 anymore?

2. Another problem may happen in the code below where waitpid is called -

    for (i = 0; i < nrcpus; i++) {
                int status;

                waitpid(pids[i], &status, 0);
                if (status != 0) {
                        fprintf(stderr, "test for cpu %d has failed\n", i);
                        ret = 1;
                }
        }

   Since for offline cpus, no child process is created, now these cpus
pid[i]'s will be zero (due to calloc). This will change the meaning of
waitpid function as man page says -

    pid 0  -    meaning wait for any child process whose process group ID
is equal to that of the calling process.

  I think a check should be added before waitpid call -

    if (pids[i] != 0)
            waitpid(pids[i], &status, 0);


​--​
​Thanks,
-Meraj​


On Wed, Apr 30, 2014 at 11:08 AM, Sanjay Singh Rawat <
sanjay.ra...@linaro.org> wrote:

> currently percpu process array is set to 2, which results in segfault
>
> Signed-off-by: Sanjay Singh Rawat <sanjay.ra...@linaro.org>
> ---
>  cpuidle/cpuidle_killer.c |    7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/cpuidle/cpuidle_killer.c b/cpuidle/cpuidle_killer.c
> index 5e7320f..09009ef 100644
> --- a/cpuidle/cpuidle_killer.c
> +++ b/cpuidle/cpuidle_killer.c
> @@ -104,7 +104,7 @@ int main(int argc, char *argv[])
>  {
>         int ret, i, nrcpus = 2;
>         int nrsleeps, delay;
> -       pid_t pids[nrcpus];
> +       pid_t *pids;
>         struct timex timex = { 0 };
>
>         if (adjtimex(&timex) < 0) {
> @@ -121,6 +121,11 @@ int main(int argc, char *argv[])
>         }
>
>         fprintf(stderr, "found %d cpu(s)\n", nrcpus);
> +       pids = (pid_t *) calloc(nrcpus, sizeof(pid_t));
> +       if (pids == NULL) {
> +               fprintf(stderr, "error: calloc failed\n");
> +               return 1;
> +       }
>
>         for (i = 0; i < nrcpus; i++) {
>
> --
> 1.7.10.4
>
>
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