Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Kurt Kanzenbach <kurt.kanzenbach@linutronix.de>
To:     Vladimir Oltean <olteanv@gmail.com>
Cc:     Alison Wang <alison.wang@nxp.com>, catalin.marinas@arm.com,
        will@kernel.org, paulmck@kernel.org, mw@semihalf.com,
        leoyang.li@nxp.com, vladimir.oltean@nxp.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Anna-Maria Gleixner <anna-maria@linutronix.de>
Subject: Re: [RFC PATCH] arm64: defconfig: Disable fine-grained task level IRQ time accounting
In-Reply-To: <20200729094943.lsmhsqlnl7rlnl6f@skbuf>
References: <20200729033934.22349-1-alison.wang@nxp.com> <877dumbtoi.fsf@kurt> <20200729094943.lsmhsqlnl7rlnl6f@skbuf>
Date:   Thu, 30 Jul 2020 09:23:44 +0200
Message-ID: <87mu3ho48v.fsf@kurt>
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="=-=-=";
        micalg=pgp-sha512; protocol="application/pgp-signature"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

--=-=-=
Content-Type: text/plain

Hi Vladimir,

On Wed Jul 29 2020, Vladimir Oltean wrote:
> For more context, here is my original report of the issue:
> https://lkml.org/lkml/2020/6/4/1062
>
> Just like you, I could not reproduce the RCU stalls and system hang on a
> 5.6-rt kernel, just on mainline and derivatives, using the plain
> defconfig.
>
> The issue is not specific to Layerscape or i.MX8, but rather I was able
> to see the same behavior on Marvell Armada 37xx as well as Qualcomm
> MSM8976.
>
> So, while of course I agree that disabling IRQ time accounting for arm64
> isn't a real solution, it isn't by far an exaggerated proposal either.
> Nonetheless, the patch is just a RFC and should be treated as such. We
> are at a loss when it comes to debugging this any further and we would
> appreciate some pointers.

Yeah, sure. I'll try to reproduce this issue first. So it triggers with:

 * arm64
 * mainline, not -rt kernel
 * opened serial console
 * irq accounting enabled

Anything else?

Thanks,
Kurt

--=-=-=
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=miKF
-----END PGP SIGNATURE-----
--=-=-=--