Re: [PATCH bpf-next 2/2] tools/bpf: add a selftest for bpf_send_signal_thread()

[Yonghong Song <yhs@fb.com>]

On 1/13/20 5:19 PM, Andrii Nakryiko wrote:
> On Thu, Jan 9, 2020 at 5:16 PM Yonghong Song <yhs@fb.com> wrote:
>>
>> The test_progs send_signal() is amended to test
>> bpf_send_signal_thread() as well.
>>
>>    $ ./test_progs -n 40
>>    #40/1 send_signal_tracepoint:OK
>>    #40/2 send_signal_perf:OK
>>    #40/3 send_signal_nmi:OK
>>    #40/4 send_signal_tracepoint_thread:OK
>>    #40/5 send_signal_perf_thread:OK
>>    #40/6 send_signal_nmi_thread:OK
>>    #40 send_signal:OK
>>    Summary: 1/6 PASSED, 0 SKIPPED, 0 FAILED
>>
>> Signed-off-by: Yonghong Song <yhs@fb.com>
>> ---
>>   tools/include/uapi/linux/bpf.h                | 18 +++++++++--
> 
> maybe do tools/uapi header sync in a first patch, along the original change?

Will do.

> 
>>   .../selftests/bpf/prog_tests/send_signal.c    | 30 ++++++++++++-------
>>   .../bpf/progs/test_send_signal_kern.c         |  9 ++++--
>>   3 files changed, 42 insertions(+), 15 deletions(-)
>>
> 
> [...]
> 
>> diff --git a/tools/testing/selftests/bpf/progs/test_send_signal_kern.c b/tools/testing/selftests/bpf/progs/test_send_signal_kern.c
>> index 0e6be01157e6..4a722024c32b 100644
>> --- a/tools/testing/selftests/bpf/progs/test_send_signal_kern.c
>> +++ b/tools/testing/selftests/bpf/progs/test_send_signal_kern.c
>> @@ -23,6 +23,7 @@ int bpf_send_signal_test(void *ctx)
>>   {
>>          __u64 *info_val, *status_val;
>>          __u32 key = 0, pid, sig;
>> +       int use_signal_thread;
>>          int ret;
>>
>>          status_val = bpf_map_lookup_elem(&status_map, &key);
>> @@ -33,11 +34,15 @@ int bpf_send_signal_test(void *ctx)
>>          if (!info_val || *info_val == 0)
>>                  return 0;
>>
>> -       sig = *info_val >> 32;
>> +       use_signal_thread = *info_val >> 48;
>> +       sig = *info_val >> 32 & 0xFFFF;
>>          pid = *info_val & 0xffffFFFF;
> 
> Would you mind rewriting this test w/ BPF skeleton and global data? It
> would make it cleaner without all this masking stuff?

Previously I made the change to minimize the number of changed lines.
But since you are mentioning rewriting here, I will do it in v2.

> 
>>
>>          if ((bpf_get_current_pid_tgid() >> 32) == pid) {
>> -               ret = bpf_send_signal(sig);
>> +               if (use_signal_thread)
>> +                       ret = bpf_send_signal_thread(sig);
>> +               else
>> +                       ret = bpf_send_signal(sig);
>>                  if (ret == 0)
>>                          *status_val = 1;
>>          }
>> --
>> 2.17.1
>>