Re: [GIT PULL] uprobes: pre-filtering

[Ingo Molnar <mingo@kernel.org>]

* Anton Arapov <anton@redhat.com> wrote:

> Hello Ingo,
> 
> On Thu, Jan 24, 2013 at 11:17 PM, Ingo Molnar <mingo@kernel.org> wrote:
> >
> > * Oleg Nesterov <oleg@redhat.com> wrote:
> >
> >> Ingo, please pull from
> >>
> >>   git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc uprobes/core
> >>
> >> Mostly pre-filtering. This needs more work and perhaps more functionality.
> >> In particular, perhaps dup_mmap() should remove the unwanted breakpoints.
> >> And we can add more ->filter() hooks to, say, speedup uprobe_register().
> >> Plus we can do some optimizations to avoid register_for_each_vma() in
> >> case when we know that all mm's were previously acked/nacked.
> >>
> >> Srikar, the only patch you did not ack explicitely is 1fecb96d
> >> "Do not allocate current->utask unnecessary", but afaics you do not
> >> object.
> >>
> >> And the patch from Josh which exports uprobe_register/unregister for modules.
> >> Christoph (cc'ed) doesn't like this change, but I disagree. Whatever you
> >> think about systemtap it is the widely used tool, and uprobes can have other
> >> out-of-tree users. This is like kprobes, kprobe_register() is exported but
> >> it doesn't have a modular in-kernel user too. I do not see why should we
> >> limit the usage of uprobes.
> >>
> >>
> >>
> >> Josh Stone (1):
> >>       uprobes: Add exports for module use
> >>
> >> Oleg Nesterov (26):
> >>       uprobes: Move __set_bit(UPROBE_SKIP_SSTEP) into alloc_uprobe()
> >>       uprobes: Kill the "uprobe != NULL" check in uprobe_unregister()
> >>       uprobes: Kill the pointless inode/uc checks in register/unregister
> >>       uprobes: Kill uprobe_consumer->filter()
> >>       uprobes: Introduce filter_chain()
> >>       uprobes: _unregister() should always do register_for_each_vma(false)
> >>       uprobes: _register() should always do register_for_each_vma(true)
> >>       uprobes: Introduce uprobe->register_rwsem
> >>       uprobes: Change filter_chain() to iterate ->consumers list
> >>       uprobes: Kill UPROBE_RUN_HANDLER flag
> >>       uprobes: Kill uprobe->copy_mutex
> >>       uprobes: Kill uprobe_events, use RB_EMPTY_ROOT() instead
> >>       uprobes: Introduce uprobe_is_active()
> >>       uprobes: Kill uprobes_mutex[], separate alloc_uprobe() and __uprobe_register()
> >>       uprobes: Rationalize the usage of filter_chain()
> >>       uprobes: Reintroduce uprobe_consumer->filter()
> >>       uprobes: Teach handler_chain() to filter out the probed task
> >>       uprobes/x86: Change __skip_sstep() to actually skip the whole insn
> >>       uprobes: Change handle_swbp() to expose bp_vaddr to handler_chain()
> >>       uprobes: Move alloc_page() from xol_add_vma() to xol_alloc_area()
> >>       uprobes: Fold xol_alloc_area() into get_xol_area()
> >>       uprobes: Turn add_utask() into get_utask()
> >>       uprobes: Do not play with utask in xol_get_insn_slot()
> >>       uprobes: Fix utask->xol_vaddr leak in pre_ssout()
> >>       uprobes: Do not allocate current->utask unnecessary
> >>       uprobes: Kill the bogus IS_ERR_VALUE(xol_vaddr) check
> >>
> >>  arch/x86/kernel/uprobes.c   |    4 +-
> >>  include/linux/uprobes.h     |   17 ++-
> >>  kernel/events/uprobes.c     |  433 ++++++++++++++++++++++---------------------
> >>  kernel/ptrace.c             |    6 +
> >>  kernel/trace/trace_uprobe.c |    5 +-
> >>  5 files changed, 243 insertions(+), 222 deletions(-)
> >
> > The kernel side looks good to me - but how does 'perf uprobe'
> > make use of it in practice, how can I test it?
> 
> I'm not sure whether you looking into testing specific changes in this
> pull, [...]

Yes, I was curious about specifically testing the filtering 
callback changes in this pull request.

Thanks,

	Ingo