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Date:   Mon, 17 Dec 2018 14:34:52 +0100
From:   Torsten Duwe <duwe@lst.de>
To:     Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc:     Will Deacon <will.deacon@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        julien.thierry@arm.com, rostedt@goodmis.org, jpoimboe@redhat.com,
        mingo@redhat.com, Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>, takahiro.akashi@linaro.org,
        LAK <linux-arm-kernel@lists.infradead.org>,
        linux-kernel@vger.kernel.org, live-patching@vger.kernel.org
Subject: Re: [PATCH v5] arm64: implement ftrace with regs
Message-ID: <20181217133450.GB5774@lst.de>
References: <20181130162015.83FE767357@newverein.lst.de> <CADGdYn46uQWfoDmRjk1OFj9fYXYbC669Ar=oVtnx141HcMFr8w@mail.gmail.com> <20181214094714.GA30043@lst.de> <CADGdYn69reXed-DBMTCezNyNEgKn-h0NA-D6dnoRrJx2_bE71Q@mail.gmail.com> <20181215134144.6b0cc45b@blackhole.lan> <CADGdYn5rrLZGrXUPA+HcKfA1pECYnwT0B1-j3YBzdt773zjORw@mail.gmail.com>
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On Mon, Dec 17, 2018 at 09:52:04AM +0530, Amit Daniel Kachhap wrote:
> There is no error message or crash but no useful output like below,
> 
> /sys/kernel/tracing # echo wake_up_process > set_graph_function
> /sys/kernel/tracing # echo function_graph > current_tracer
> /sys/kernel/tracing # cat trace
> # tracer: function_graph
> #
> # CPU  DURATION                  FUNCTION CALLS
> # |     |   |                     |   |   |   |

Confirmed. The graph tracer self-test passes, but when used, there is no
output.

	Torsten