From: arnaldo.melo@gmail.com
To: Song Liu <songliubraving@fb.com>,Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
"joonas.lahtinen@linux.intel.com"
<joonas.lahtinen@linux.intel.com>,
Will Deacon <will.deacon@arm.com>,
Alexei Starovoitov <ast@kernel.org>,
Stephane Eranian <eranian@google.com>,
"james.bottomley@hansenpartnership.com"
<james.bottomley@hansenpartnership.com>,
Paul Mackerras <paulus@samba.org>, Jiri Olsa <jolsa@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
Alexey Budankov <alexey.budankov@linux.intel.com>,
Igor Lubashev <ilubashe@akamai.com>,
James Morris <jmorris@namei.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>, Serge Hallyn <serge@hallyn.com>,
Robert Richter <rric@kernel.org>,
"jani.nikula@linux.intel.com" <jani.nikula@linux.intel.com>,
"rodrigo.vivi@intel.com" <rodrigo.vivi@intel.com>,
Namhyung Kim <namhyung@kernel.org>,
Kees@lists.ozlabs.org, Casey Schaufler <casey@schaufler-ca.com>
Subject: Re: [PATCH v4 2/9] perf/core: open access for CAP_SYS_PERFMON privileged process
Date: Fri, 10 Jan 2020 21:35:12 -0300 [thread overview]
Message-ID: <5e191833.1c69fb81.8bc25.a88c@mx.google.com> (raw)
In-Reply-To: <2B79131A-3F76-47F5-AAB4-08BCA820473F@fb.com>
<keescook@chromium.org>,Jann Horn <jannh@google.com>,Thomas Gleixner <tglx@linutronix.de>,Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,Lionel Landwerlin <lionel.g.landwerlin@intel.com>,linux-kernel <linux-kernel@vger.kernel.org>,"linux-security-module@vger.kernel.org" <linux-security-module@vger.kernel.org>,"selinux@vger.kernel.org" <selinux@vger.kernel.org>,"intel-gfx@lists.freedesktop.org" <intel-gfx@lists.freedesktop.org>,"bpf@vger.kernel.org" <bpf@vger.kernel.org>,"linux-parisc@vger.kernel.org" <linux-parisc@vger.kernel.org>,"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,"linux-perf-users@vger.kernel.org" <linux-perf-users@vger.kernel.org>,"linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>,"oprofile-list@lists.sf.net" <oprofile-list@lists.sf.net>
From: Arnaldo Carvalho de Melo <acme@kernel.org>
Message-ID: <A7F0BF73-9189-44BA-9264-C88F2F51CBF3@kernel.org>
On January 10, 2020 9:23:27 PM GMT-03:00, Song Liu <songliubraving@fb.com> wrote:
>
>
>> On Jan 10, 2020, at 3:47 PM, Masami Hiramatsu <mhiramat@kernel.org>
>wrote:
>>
>> On Fri, 10 Jan 2020 13:45:31 -0300
>> Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
>>
>>> Em Sat, Jan 11, 2020 at 12:52:13AM +0900, Masami Hiramatsu escreveu:
>>>> On Fri, 10 Jan 2020 15:02:34 +0100 Peter Zijlstra
><peterz@infradead.org> wrote:
>>>>> Again, this only allows attaching to previously created kprobes,
>it does
>>>>> not allow creating kprobes, right?
>>>
>>>>> That is; I don't think CAP_SYS_PERFMON should be allowed to create
>>>>> kprobes.
>>>
>>>>> As might be clear; I don't actually know what the user-ABI is for
>>>>> creating kprobes.
>>>
>>>> There are 2 ABIs nowadays, ftrace and ebpf. perf-probe uses ftrace
>interface to
>>>> define new kprobe events, and those events are treated as
>completely same as
>>>> tracepoint events. On the other hand, ebpf tries to define new
>probe event
>>>> via perf_event interface. Above one is that interface. IOW, it
>creates new kprobe.
>>>
>>> Masami, any plans to make 'perf probe' use the perf_event_open()
>>> interface for creating kprobes/uprobes?
>>
>> Would you mean perf probe to switch to perf_event_open()?
>> No, perf probe is for setting up the ftrace probe events. I think we
>can add an
>> option to use perf_event_open(). But current kprobe creation from
>perf_event_open()
>> is separated from ftrace by design.
>
>I guess we can extend event parser to understand kprobe directly.
>Instead of
>
> perf probe kernel_func
> perf stat/record -e probe:kernel_func ...
>
>We can just do
>
> perf stat/record -e kprobe:kernel_func ...
You took the words from my mouth, exactly, that is a perfect use case, an alternative to the 'perf probe' one of making a disabled event that then gets activated via record/stat/trace, in many cases it's better, removes the explicit probe setup case.
Regards,
- Arnaldo
>
>Thanks,
>Song
next prev parent reply other threads:[~2020-01-11 7:57 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 9:16 [PATCH v4 0/7] Introduce CAP_SYS_PERFMON to secure system performance monitoring and observability Alexey Budankov
2019-12-18 9:24 ` [PATCH v4 1/9] capabilities: introduce CAP_SYS_PERFMON to kernel and user space Alexey Budankov
2019-12-18 19:56 ` Stephen Smalley
2019-12-28 3:53 ` Serge E. Hallyn
2020-01-13 20:25 ` Song Liu
2019-12-18 9:25 ` [PATCH v4 2/9] perf/core: open access for CAP_SYS_PERFMON privileged process Alexey Budankov
2020-01-08 16:07 ` Peter Zijlstra
2020-01-09 11:36 ` Alexey Budankov
2020-01-10 14:02 ` Peter Zijlstra
2020-01-10 15:52 ` Masami Hiramatsu
2020-01-10 16:45 ` Arnaldo Carvalho de Melo
2020-01-10 23:47 ` Masami Hiramatsu
2020-01-11 0:23 ` Song Liu
2020-01-11 0:35 ` arnaldo.melo [this message]
2020-01-12 1:44 ` Masami Hiramatsu
2020-01-10 16:41 ` Alexey Budankov
2020-01-10 17:34 ` Alexey Budankov
2019-12-18 9:26 ` [PATCH v4 3/9] perf tool: extend Perf tool with CAP_SYS_PERFMON capability support Alexey Budankov
2019-12-18 9:27 ` [PATCH v4 4/9] drm/i915/perf: open access for CAP_SYS_PERFMON privileged process Alexey Budankov
2019-12-19 9:10 ` Lionel Landwerlin
2019-12-18 9:28 ` [PATCH v4 5/9] trace/bpf_trace: " Alexey Budankov
2020-01-13 20:47 ` Song Liu
2019-12-18 9:28 ` [PATCH v4 6/9] powerpc/perf: " Alexey Budankov
2019-12-18 9:29 ` [PATCH v4 7/9] parisc/perf: " Alexey Budankov
2020-01-27 8:52 ` Helge Deller
2019-12-18 9:30 ` [PATCH v4 8/9] drivers/perf: " Alexey Budankov
2020-01-17 10:51 ` Will Deacon
2020-01-17 21:33 ` Alexey Budankov
2019-12-18 9:31 ` [PATCH v4 9/9] drivers/oprofile: " Alexey Budankov
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