* Detecting kprobes generated code addresses
@ 2016-12-22 6:40 Josh Poimboeuf
0 siblings, 0 replies; 5+ messages in thread
From: Josh Poimboeuf @ 2016-12-22 6:40 UTC (permalink / raw)
To: Masami Hiramatsu; +Cc: linux-kernel, x86
Hi Masami,
I would like to make __kernel_text_address() be able to detect whether
an address belongs to code which was generated by kprobes. As far as I
can tell, that information seems to be in the 'pages' lists of
kprobe_insn_slots and kprobe_optinsn_slots. But they seem to be
protected by mutexes. Do you know if there's a sleep-free way to access
that
protected
--
Josh
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Detecting kprobes generated code addresses
2016-12-25 6:16 ` Masami Hiramatsu
@ 2016-12-26 4:30 ` Masami Hiramatsu
0 siblings, 0 replies; 5+ messages in thread
From: Masami Hiramatsu @ 2016-12-26 4:30 UTC (permalink / raw)
To: Masami Hiramatsu; +Cc: Josh Poimboeuf, linux-kernel, x86
On Sun, 25 Dec 2016 15:16:00 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:
> On Sun, 25 Dec 2016 12:13:20 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> > On Thu, 22 Dec 2016 00:42:19 -0600
> > Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> >
> > > Hi Masami,
> > >
> > > I would like to make __kernel_text_address() be able to detect whether
> > > an address belongs to code which was generated by kprobes. As far as I
> > > can tell, that information seems to be in the 'pages' lists of
> > > kprobe_insn_slots and kprobe_optinsn_slots. But they seem to be
> > > protected by mutexes.
> >
> > Right. It is currently under mutex because it may kick
> > page allocation. But I think it is easy to fix that :)
>
> Hmm, IMHO, it seems that we should add a dummy (auto-generated)
> symbol for optprobe trampoline code to kallsyms so that
> __kernel_text_address() automatically returns true on it.
Sorry, I reconsidered this idea and conclude it was overkill.
As same as ftrace does, maybe it is enough to add a check
routine to __kernel_text_address().
Thanks,
--
Masami Hiramatsu <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Detecting kprobes generated code addresses
2016-12-25 3:13 ` Masami Hiramatsu
@ 2016-12-25 6:16 ` Masami Hiramatsu
2016-12-26 4:30 ` Masami Hiramatsu
0 siblings, 1 reply; 5+ messages in thread
From: Masami Hiramatsu @ 2016-12-25 6:16 UTC (permalink / raw)
To: Masami Hiramatsu; +Cc: Josh Poimboeuf, linux-kernel, x86
On Sun, 25 Dec 2016 12:13:20 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:
> On Thu, 22 Dec 2016 00:42:19 -0600
> Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>
> > Hi Masami,
> >
> > I would like to make __kernel_text_address() be able to detect whether
> > an address belongs to code which was generated by kprobes. As far as I
> > can tell, that information seems to be in the 'pages' lists of
> > kprobe_insn_slots and kprobe_optinsn_slots. But they seem to be
> > protected by mutexes.
>
> Right. It is currently under mutex because it may kick
> page allocation. But I think it is easy to fix that :)
Hmm, IMHO, it seems that we should add a dummy (auto-generated)
symbol for optprobe trampoline code to kallsyms so that
__kernel_text_address() automatically returns true on it.
Thank you,
--
Masami Hiramatsu <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Detecting kprobes generated code addresses
2016-12-22 6:42 Josh Poimboeuf
@ 2016-12-25 3:13 ` Masami Hiramatsu
2016-12-25 6:16 ` Masami Hiramatsu
0 siblings, 1 reply; 5+ messages in thread
From: Masami Hiramatsu @ 2016-12-25 3:13 UTC (permalink / raw)
To: Josh Poimboeuf; +Cc: linux-kernel, x86
On Thu, 22 Dec 2016 00:42:19 -0600
Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> Hi Masami,
>
> I would like to make __kernel_text_address() be able to detect whether
> an address belongs to code which was generated by kprobes. As far as I
> can tell, that information seems to be in the 'pages' lists of
> kprobe_insn_slots and kprobe_optinsn_slots. But they seem to be
> protected by mutexes.
Right. It is currently under mutex because it may kick
page allocation. But I think it is easy to fix that :)
> Do you know if there's a sleep-free way to access
> that information?
Hmm, no, I couldn't find that yet.
Thanks,
--
Masami Hiramatsu <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Detecting kprobes generated code addresses
@ 2016-12-22 6:42 Josh Poimboeuf
2016-12-25 3:13 ` Masami Hiramatsu
0 siblings, 1 reply; 5+ messages in thread
From: Josh Poimboeuf @ 2016-12-22 6:42 UTC (permalink / raw)
To: Masami Hiramatsu; +Cc: linux-kernel, x86
Hi Masami,
I would like to make __kernel_text_address() be able to detect whether
an address belongs to code which was generated by kprobes. As far as I
can tell, that information seems to be in the 'pages' lists of
kprobe_insn_slots and kprobe_optinsn_slots. But they seem to be
protected by mutexes. Do you know if there's a sleep-free way to access
that information?
--
Josh
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-12-26 4:30 UTC | newest]
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2016-12-22 6:40 Detecting kprobes generated code addresses Josh Poimboeuf
2016-12-22 6:42 Josh Poimboeuf
2016-12-25 3:13 ` Masami Hiramatsu
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2016-12-26 4:30 ` Masami Hiramatsu
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