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| author | Taeung Song <treeze.taeung@gmail.com> | 2018-07-04 22:36:37 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-08-24 13:09:12 +0200 |
| commit | 3bbb0484a7317707243306352ad5457f64104d68 (patch) | |
| tree | 88238e8b2cd0fac45d6ef9e9689c0b4f0105adce /samples | |
| parent | 2b533daef882f7ac6faa46e6e0e47589df1b8e7f (diff) | |
samples/bpf: Check the result of system()
[ Upstream commit 492b7e894587c151be681f86d4d1d086375f7b45 ]
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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/bpf/trace_event_user.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c index 7bd827b84a67..c7d525e5696e 100644 --- a/samples/bpf/trace_event_user.c +++ b/samples/bpf/trace_event_user.c @@ -121,6 +121,16 @@ 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); @@ -138,7 +148,11 @@ 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--) { @@ -152,7 +166,7 @@ all_cpu_err: static void test_perf_event_task(struct perf_event_attr *attr) { - int pmu_fd; + int pmu_fd, error = 0; /* open task bound event */ pmu_fd = sys_perf_event_open(attr, 0, -1, -1, 0); @@ -162,10 +176,17 @@ 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) |