Fix the following warns by adding return check and error handling.

gcc -O2 -Wall -g -I./ -isystem .../tools/testing/selftests/../../../usr/include -Wl,-rpath=./ cs_prctl_test.c -lpthread -o .../tools/testing/selftests/sched/cs_prctl_test cs_prctl_test.c: In function ‘create_processes’: cs_prctl_test.c:187:17: warning: ignoring return value of ‘read’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 187 | read(proc[i].pfd[0], &proc[i].thr_tids, sizeof(int) * proc[i].num_threads); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cs_prctl_test.c: In function ‘child_func_process’: cs_prctl_test.c:159:9: warning: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 159 | write(ca->pfd[1], &ca->thr_tids, sizeof(int) * ca->num_threads); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Shuah Khan skhan@linuxfoundation.org --- tools/testing/selftests/sched/cs_prctl_test.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/sched/cs_prctl_test.c b/tools/testing/selftests/sched/cs_prctl_test.c index 8109b17dc764..25e0d95d3713 100644 --- a/tools/testing/selftests/sched/cs_prctl_test.c +++ b/tools/testing/selftests/sched/cs_prctl_test.c @@ -27,6 +27,7 @@ #include <sys/prctl.h> #include <unistd.h> #include <time.h> +#include <errno.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -151,12 +152,17 @@ static void create_threads(int num_threads, int thr_tids[]) static int child_func_process(void *arg) { struct child_args *ca = (struct child_args *)arg; + int ret;

close(ca->pfd[0]);

create_threads(ca->num_threads, ca->thr_tids);

- write(ca->pfd[1], &ca->thr_tids, sizeof(int) * ca->num_threads); + ret = write(ca->pfd[1], &ca->thr_tids, sizeof(int) * ca->num_threads); + if (ret == -1) + printf("write failed on pfd[%d] - error (%s)\n", + ca->pfd[1], strerror(errno)); + close(ca->pfd[1]);

while (1) @@ -169,7 +175,7 @@ static unsigned char child_func_process_stack[STACK_SIZE]; void create_processes(int num_processes, int num_threads, struct child_args proc[]) { pid_t cpid; - int i; + int i, ret;

for (i = 0; i < num_processes; ++i) { proc[i].num_threads = num_threads; @@ -184,7 +190,10 @@ void create_processes(int num_processes, int num_threads, struct child_args proc }

for (i = 0; i < num_processes; ++i) { - read(proc[i].pfd[0], &proc[i].thr_tids, sizeof(int) * proc[i].num_threads); + ret = read(proc[i].pfd[0], &proc[i].thr_tids, sizeof(int) * proc[i].num_threads); + if (ret == -1) + printf("read failed on proc[%d].pfd[0] error (%s)\n", + i, strerror(errno)); close(proc[i].pfd[0]); } }