Re: [PATCH v2 bpf-next 3/4] selftests/bpf: Add profiler test

[Song Liu]

On Tue, Oct 13, 2020 at 12:57 PM Jiri Olsa <jo...@redhat.com> wrote:
>
> On Thu, Oct 08, 2020 at 06:12:39PM -0700, Alexei Starovoitov wrote:
>
> SNIP
>
> > +
> > +#ifdef UNROLL
> > +#pragma unroll
> > +#endif
> > +     for (int i = 0; i < MAX_CGROUPS_PATH_DEPTH; i++) {
> > +             filepart_length =
> > +                     bpf_probe_read_str(payload, MAX_PATH, 
> > BPF_CORE_READ(cgroup_node, name));
> > +             if (!cgroup_node)
> > +                     return payload;
> > +             if (cgroup_node == cgroup_root_node)
> > +                     *root_pos = payload - payload_start;
> > +             if (filepart_length <= MAX_PATH) {
> > +                     barrier_var(filepart_length);
> > +                     payload += filepart_length;
> > +             }
> > +             cgroup_node = BPF_CORE_READ(cgroup_node, parent);
> > +     }
> > +     return payload;
> > +}
> > +
> > +static ino_t get_inode_from_kernfs(struct kernfs_node* node)
> > +{
> > +     struct kernfs_node___52* node52 = (void*)node;
> > +
> > +     if (bpf_core_field_exists(node52->id.ino)) {
> > +             barrier_var(node52);
> > +             return BPF_CORE_READ(node52, id.ino);
> > +     } else {
> > +             barrier_var(node);
> > +             return (u64)BPF_CORE_READ(node, id);
> > +     }
> > +}
> > +
> > +int pids_cgrp_id = 1;
>
>
> hi,
> I'm getting compilation failure with this:
>
>           CLNG-LLC [test_maps] profiler2.o
>         In file included from progs/profiler2.c:6:
>         progs/profiler.inc.h:246:5: error: redefinition of 'pids_cgrp_id' as 
> different kind of symbol
>         int pids_cgrp_id = 1;
>             ^
>         
> /home/jolsa/linux-qemu/tools/testing/selftests/bpf/tools/include/vmlinux.h:14531:2:
>  note: previous definition is here
>                 pids_cgrp_id = 11,
>                 ^
>         1 error generated.
>         /opt/clang/bin/llc: error: /opt/clang/bin/llc: <stdin>:1:1: error: 
> expected top-level entity
>         BPF obj compilation failed
>         ^
>         make: *** [Makefile:396: 
> /home/jolsa/linux-qemu/tools/testing/selftests/bpf/profiler2.o] Error 1

I got the same error with some .config. We should fix it with something below.

I will send official patch soon.

Thanks,
Song

diff --git i/tools/testing/selftests/bpf/progs/profiler.inc.h
w/tools/testing/selftests/bpf/progs/profiler.inc.h
index 00578311a4233..54f594efccbca 100644
--- i/tools/testing/selftests/bpf/progs/profiler.inc.h
+++ w/tools/testing/selftests/bpf/progs/profiler.inc.h
@@ -243,7 +243,7 @@ static ino_t get_inode_from_kernfs(struct kernfs_node* node)
        }
 }

-int pids_cgrp_id = 1;
+int pids_cgrp_id_ = 1;

 static INLINE void* populate_cgroup_info(struct cgroup_data_t* cgroup_data,
                                         struct task_struct* task,
@@ -262,7 +262,7 @@ static INLINE void* populate_cgroup_info(struct
cgroup_data_t* cgroup_data,
                                BPF_CORE_READ(task, cgroups, subsys[i]);
                        if (subsys != NULL) {
                                int subsys_id = BPF_CORE_READ(subsys, ss, id);
-                               if (subsys_id == pids_cgrp_id) {
+                               if (subsys_id == pids_cgrp_id_) {
                                        proc_kernfs =
BPF_CORE_READ(subsys, cgroup, kn);
                                        root_kernfs =
BPF_CORE_READ(subsys, ss, root, kf_root, kn);
                                        break;