Re: [GIT PULL] uprobes: pre-filtering

[Ingo Molnar <mingo@kernel.org>]

* 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?

Thanks,

	Ingo