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From:   Vladimir Oltean <vladimir.oltean@nxp.com>
To:     Marc Kleine-Budde <mkl@pengutronix.de>
CC:     Vladimir Oltean <olteanv@gmail.com>,
        "wg@grandegger.com" <wg@grandegger.com>,
        Pankaj Bansal <pankaj.bansal@nxp.com>,
        "Pankaj Bansal (OSS)" <pankaj.bansal@oss.nxp.com>,
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        Joakim Zhang <qiangqing.zhang@nxp.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: canfdtest on flexcan loopback
Thread-Topic: canfdtest on flexcan loopback
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Date:   Fri, 18 Sep 2020 12:27:17 +0000
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On Thu, Sep 17, 2020 at 03:10:28PM +0200, Marc Kleine-Budde wrote:
> On 9/17/20 2:59 PM, Vladimir Oltean wrote:
> > On Wed, Sep 16, 2020 at 03:14:37PM +0300, Vladimir Oltean wrote:
> >> Nonetheless, you bring up a good point. I'll try to bring into net-nex=
t
> >> the minimum amount of required delta (which seems to be the
> >> fsl_lx2160a_r1_devtype_data structure only), and I'll re-test.
> >
> > So I'm back with some interesting results.
> >
> > Test 1:
> > NXP LSDK 20.04 based on v5.4.3 - reordering reproduces instantly
> >
> > Test 2:
> > net-next 5.9-rc3 with upstream defconfig and all downstream patches
> > imported from LSDK - hasn't reproduced in 20 hours of testing
> >
> > Test 3:
> > net-next 5.9-rc3 with .config imported from LSDK - hasn't reproduced in
> > 335 iterations
> >
> > Test 4:
> > linux stable linux-5.4.y - hasn't reproduced in 137 iterations
> >
> > Test 5:
> > torvalds v5.4.3 - reproduces instantly
>
> Is there a bug in v5.4.3? v5.4.66 is current latest v5.4.x
>
> Marc
>
> --
> Pengutronix e.K.                 | Marc Kleine-Budde           |
> Embedded Linux                   | https://www.pengutronix.de  |
> Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
> Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
>

63d5320a0c9b9867628a3a5a12e7f11d4cc109c2 is the first fixed commit

commit 63d5320a0c9b9867628a3a5a12e7f11d4cc109c2
Author: Paolo Abeni <pabeni@redhat.com>
Date:   Tue Feb 18 18:15:44 2020 +0100

    Revert "net: dev: introduce support for sch BYPASS for lockless qdisc"

    [ Upstream commit 379349e9bc3b42b8b2f8f7a03f64a97623fff323 ]

    This reverts commit ba27b4cdaaa66561aaedb2101876e563738d36fe

    Ahmed reported ouf-of-order issues bisected to commit ba27b4cdaaa6
    ("net: dev: introduce support for sch BYPASS for lockless qdisc").
    I can't find any working solution other than a plain revert.

    This will introduce some minor performance regressions for
    pfifo_fast qdisc. I plan to address them in net-next with more
    indirect call wrapper boilerplate for qdiscs.

    Reported-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
    Fixes: ba27b4cdaaa6 ("net: dev: introduce support for sch BYPASS for lo=
ckless qdisc")
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 net/core/dev.c | 22 ++--------------------
 1 file changed, 2 insertions(+), 20 deletions(-)=