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authorTaeung Song <treeze.taeung@gmail.com>2018-07-04 22:36:37 +0900
committerDaniel Borkmann <daniel@iogearbox.net>2018-07-05 09:58:52 +0200
commit492b7e894587c151be681f86d4d1d086375f7b45 (patch)
tree20f39b54a83769caa0867f5898ef4521b21d16d5 /samples
parent4d5d33a085335ef469c9a87792bcaaaa8e64d8c4 (diff)
downloadlinux-492b7e894587c151be681f86d4d1d086375f7b45.tar.bz2
samples/bpf: Check the result of system()
To avoid the below build warning message, use new generate_load() checking the return value. ignoring return value of ‘system’, declared with attribute warn_unused_result And it also refactors the duplicate code of both test_perf_event_all_cpu() and test_perf_event_task() Cc: Teng Qin <qinteng@fb.com> Signed-off-by: Taeung Song <treeze.taeung@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'samples')
-rw-r--r--samples/bpf/trace_event_user.c27
1 files changed, 24 insertions, 3 deletions
diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
index 1fa1becfa641..d08046ab81f0 100644
--- a/samples/bpf/trace_event_user.c
+++ b/samples/bpf/trace_event_user.c
@@ -122,6 +122,16 @@ static void print_stacks(void)
}
}
+static inline int generate_load(void)
+{
+ if (system("dd if=/dev/zero of=/dev/null count=5000k status=none") < 0) {
+ printf("failed to generate some load with dd: %s\n", strerror(errno));
+ return -1;
+ }
+
+ return 0;
+}
+
static void test_perf_event_all_cpu(struct perf_event_attr *attr)
{
int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
@@ -142,7 +152,11 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
}
- system("dd if=/dev/zero of=/dev/null count=5000k status=none");
+
+ if (generate_load() < 0) {
+ error = 1;
+ goto all_cpu_err;
+ }
print_stacks();
all_cpu_err:
for (i--; i >= 0; i--) {
@@ -156,7 +170,7 @@ all_cpu_err:
static void test_perf_event_task(struct perf_event_attr *attr)
{
- int pmu_fd;
+ int pmu_fd, error = 0;
/* per task perf event, enable inherit so the "dd ..." command can be traced properly.
* Enabling inherit will cause bpf_perf_prog_read_time helper failure.
@@ -171,10 +185,17 @@ static void test_perf_event_task(struct perf_event_attr *attr)
}
assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
- system("dd if=/dev/zero of=/dev/null count=5000k status=none");
+
+ if (generate_load() < 0) {
+ error = 1;
+ goto err;
+ }
print_stacks();
+err:
ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
close(pmu_fd);
+ if (error)
+ int_exit(0);
}
static void test_bpf_perf_event(void)