Messages in this thread | | | Date | Thu, 18 Sep 2014 16:50:04 +0200 | From | Daniel Borkmann <> | Subject | Re: [PATCH v13 net-next 07/11] bpf: verifier (add ability to receive verification log) |
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On 09/18/2014 04:34 PM, Alexei Starovoitov wrote: > On Wed, Sep 17, 2014 at 11:44 PM, Daniel Borkmann <dborkman@redhat.com> wrote: ... >> Sure, you will never get a full compatibility on that regard >> while backwards compatibility needs to be guaranteed on the >> other hand. I looked at perf_copy_attr() implementation and I >> think that we should mimic it in a very similar way as it >> exactly solves what we need. >> >> For example, it will return with -EINVAL for (size > PAGE_SIZE) >> and (size < PERF_ATTR_SIZE_VER0) where PAGE_SIZE has been chosen >> as an arbitrary hard upper limit where it is believed that it will >> never grow beyond that large limit in future. >> >> So this is a more loose constraint than what we currently do, >> that is, -EINVAL on (size > sizeof(attr)) where attr is the >> currently known size of a specific kernel. That would at least >> be a start, you won't be able to cover everything though, but >> it would allow to address the issue raised when running with >> a basic feature set. > > you missed my point. We should not 'do a start', since it > doesn't help user space in the long run and only makes > kernel more complex.
Sorry, I don't think I missed your point. But if you see things differently, fair enough, it was just a suggestion.
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