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Date:   Thu, 1 Nov 2018 21:49:48 +1100
From:   Aleksa Sarai <cyphar@cyphar.com>
To:     Masami Hiramatsu <mhiramat@kernel.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Brendan Gregg <bgregg@netflix.com>,
        Christian Brauner <christian@brauner.io>,
        Aleksa Sarai <asarai@suse.de>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kretprobe: produce sane stack traces
Message-ID: <20181101104948.bc7wk453bfryhhk7@yavin>
References: <20181026132210.12569-1-cyphar@cyphar.com>
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On 2018-11-01, Masami Hiramatsu <mhiramat@kernel.org> wrote:
> > > > Anyway, until that merge happens, this patch looks good to avoid
> > > > this issue for generic solution (e.g. for the arch which doesn't
> > > > supports retstack).
> > >=20
> > > I think its time to come up with an algorithm that makes function gra=
ph
> > > work with multiple users, and have kretprobes be able to hook into it
> > > just like kprobes hooks into function tracer.
> > >=20
> > > I have some ideas on how to get this done, and will try to have an RFC
> > > patch set ready by plumbers.
> >=20
> > Should I continue working on this patchset?
>=20
> Yes, until we finally introduce Steven's algorithm on all arch (yeah, we =
still
> have some archs which don't support graph-tracer but supports kprobes),
> I think your patch is the best fix for this issue.

Thanks, I just sent a v3.

Though, even with Steven's hooking of kprobes I think you'd still need
to stash away the stack trace somewhere (or am I misunderstanding the
proposal?).

--=20
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>

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