On 06/06/2018 06:12 PM, Yonghong Song wrote: > Commit f269099a7e7a ("tools/bpf: add a selftest for > bpf_get_current_cgroup_id() helper") added a test > for bpf_get_current_cgroup_id() helper. The bpf program > is attached to tracepoint syscalls/sys_enter_nanosleep > and will record the cgroup id if the tracepoint is hit. > The test program creates a cgroup and attachs itself to > this cgroup and expects that the test program process > cgroup id is the same as the cgroup_id retrieved > by the bpf program. > > In a light system where no other processes called > nanosleep syscall, the test case can pass. > In a busy system where many different processes can hit > syscalls/sys_enter_nanosleep tracepoint, the cgroup id > recorded by bpf program may not match the test program > process cgroup_id. > > This patch fixed an issue by communicating the test program > pid to bpf program. The bpf program only records > cgroup id if the current task pid is the same as > passed-in pid. This ensures that the recorded cgroup_id > is for the cgroup within which the test program resides. > > Fixes: f269099a7e7a ("tools/bpf: add a selftest for > bpf_get_current_cgroup_id() helper") > Signed-off-by: Yonghong Song <y...@fb.com>
Applied to bpf, thanks Yonghong!