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    SubjectRe: 2.6.24-rc3: find complains about /proc/net
    Date
    Ulrich Drepper <drepper@redhat.com> writes:

    > Roland McGrath wrote:
    >> Oh, it seems it has indeed been that way for a very long time, so I was
    >> mistaken. It still seems a little odd to me. Ulrich can say definitively
    >> whether the kind of concern I mentioned really matters one way or the other
    >> for glibc.
    >
    > glibc cannot survive (at least NPTL) if somebody uses funny CLONE_*
    > flags to separate various pieces of information, e.g., file descriptors.
    > So, all the information in each thread's /proc/self should be identical.

    Which seems to confirm that glibc and native pthread can't care.

    > When the information is not the same, the current semantics seems to be
    > more useful. So I guess, no change is the way to go here.

    Could you elaborate a bit on how the semantics of returning the
    wrong information are more useful?

    In particular if a thread does the logical equivalent of:
    grep Pid: /proc/self/status. It always get the tgid despite
    having a different process id.

    How can that possibly be useful or correct?

    From the kernel side I really think the current semantics of /proc/self
    in the context of threads is a bug and confusing. All of the kernel
    developers first reaction when this was pointed out was that this
    is a regression.

    If it is truly useful to user space we can preserve this API design
    bug forever. I just want to make certain we are not being bug
    compatible without a good reason.

    Currently we have several kernel side bugs with threaded
    programs because /proc/self does not do the intuitive thing. Unless
    something has changed recently selinux will cause accesses by a
    non-leader thread to fail when accessing files through /proc/self.

    So far the more I look at the current /proc/self behavior the
    more I am convinced it is broken, and useless. Please help me see
    where it is useful, so we can justify keeping it.

    Thanks,
    Eric
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