On Wednesday 30 April 2014 12:14 PM, Mohammad Merajul Islam Molla wrote:
Hello,
I would like to share two observations -
- Is it necessary to initialize nrcpus = 2 anymore?
thanks, ack
- 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);
Here Parent will not wait for child infinitely if status is not visible, the option argument is 0(NOHANG). I will add the macro for readability. thanks
-- Thanks, -Meraj
On Wed, Apr 30, 2014 at 11:08 AM, Sanjay Singh Rawat <sanjay.rawat@linaro.org mailto:sanjay.rawat@linaro.org> wrote:
currently percpu process array is set to 2, which results in segfault Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org <mailto:sanjay.rawat@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 _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org <mailto:linaro-dev@lists.linaro.org> http://lists.linaro.org/mailman/listinfo/linaro-dev