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

On Tue, Oct 13, 2020 at 12:57 PM Jiri Olsa [off-list ref] wrote:

On Thu, Oct 08, 2020 at 06:12:39PM -0700, Alexei Starovoitov wrote:

SNIP

quoted

+
+#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;