On 30-Aug 19:24, Song Liu wrote:

quoted

On Aug 30, 2019, at 11:53 AM, Anton Protopopov [off-list ref] wrote:

чт, 29 авг. 2019 г. в 16:02, Song Liu [off-list ref]:

quoted

quoted

On Aug 14, 2019, at 5:03 PM, Anton Protopopov [off-list ref] wrote:

[...]

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int bpf_object__unload(struct bpf_object *obj)

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index e8f70977d137..634f278578dd 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h

@@ -63,8 +63,13 @@ LIBBPF_API libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn);

struct bpf_object;

struct bpf_object_open_attr {
-     const char *file;
+     union {
+             const char *file;
+             const char *obj_name;
+     };
     enum bpf_prog_type prog_type;
+     void *obj_buf;
+     size_t obj_buf_sz;
};

I think this would break dynamically linked libbpf. No?

Ah, yes, sure. What is the right way to make changes which break ABI in libbpf?

I don't have a good idea here on the top of my head.

Maybe we need a new struct and/or function for this. 

I incorporated the suggested fixes and sent a new patch for this as we
ran into pretty much the same issue. (i.e. not being able to set
needs_kver / flags).

https://lore.kernel.org/bpf/20190927130834.18829-1-kpsingh@chromium.org/T/#u (local)

- KP

quoted

BTW, does the commit ddc7c3042614 ("libbpf: implement BPF CO-RE offset
relocation algorithm") which adds a new field to the struct
bpf_object_load_attr also break ABI?

I think this change was in the same release, so it is OK. 

Thanks,
Song