On Wed, Dec 12, 2018 at 06:56:11PM +0000, Song Liu wrote:
>
>
> > On Dec 12, 2018, at 10:05 AM, Peter Zijlstra <pet...@infradead.org> wrote:
> >
> > On Wed, Dec 12, 2018 at 05:09:17PM +0000, Song Liu wrote:
> >>> And while this tracks the bpf kallsyms, it does not do all kallsyms.
> >>>
> >>> .... Oooh, I see the problem, everybody is doing their own custom
> >>> kallsym_{add,del}() thing, instead of having that in generic code :-(
> >>>
> >>> This, for example, doesn't track module load/unload nor ftrace
> >>> trampolines, even though both affect kallsyms.
> >>
> >> I think we can use PERF_RECORD_MMAP(or MMAP2) for module load/unload.
> >> That could be separate sets of patches.
> >
> > So I would actually like to move bpf_lock/bpf_kallsyms/bpf_tree +
> > bpf_prog_kallsyms_*() + __bpf_address_lookup() into kernel/kallsyms.c
> > and also have ftrace use that.
> >
> > Because currently the ftrace stuff is otherwise invisible.
> >
> > A generic kallsym register/unregister for any JIT.
>
> I guess this is _not_ a requirement for this patchset? BPF program has
> special data (id, sub_id, tag) that we need PERF_RECORD_BPF_EVENT. So
> this patchset should be orthogonal to the generic kallsym framework?
Well, it is a question of ABI. I don't like mixing the kallsym updates
with the BPF updates.
