From: Andrew Lunn <andrew@lunn.ch>
To: Cedric Jehasse <cedric.jehasse@gmail.com>
Cc: "Luke Howard" <lukeh@padl.com>,
cedric.jehasse@luminex.be, "Vladimir Oltean" <olteanv@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Simon Horman" <horms@kernel.org>,
"Russell King" <linux@armlinux.org.uk>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
"Marek Behún" <kabel@kernel.org>
Subject: Re: [PATCH net-next v4 2/2] net: dsa: mv88e6xxx: add support for credit based shaper
Date: Fri, 29 May 2026 16:38:45 +0200 [thread overview]
Message-ID: <921845db-734b-4241-9c87-9f035bcb6bb2@lunn.ch> (raw)
In-Reply-To: <rqvaiyu7qm2il4vhdhgwschodlw77fqd6hiszuwmffjvdthtkc@do7mmsdz77qf>
On Fri, May 29, 2026 at 04:32:15PM +0200, Cedric Jehasse wrote:
> On Fri, May 29, 2026 at 03:28:56PM +0200, Andrew Lunn wrote:
> > > > That's not the same logic.
> > > > If one of the two function pointer is NULL, the other can still be executed
> > > > (Maybe not that likely as that's probably a mistake in the driver)
> > >
> > > True, but agree also that it shouldn’t happen (would be a driver bug).
> >
> > However, a kernel splat because you have jumped through a NULL pointer
> > makes a good bug report. It is much more obvious what is wrong than a
> > report that somebody tried to configure TC, but nothing appeared to
> > happen.
> >
>
> Removing !avb_ops->port_qav_write || !ops->port_set_scheduling_mode won't make
> it jump to a NULL pointer. mv88e6xxx_port_qav_write and
> mv88e6xxx_port_set_scheduling_mode will still return -EOPNOTSUPP.
> Do you prefer removing the NULL pointer checks in those functions?
No, leave them. Its just people have an aversion to kernel splats, but
they can actually be useful if they highlight a bug.
Andrew
prev parent reply other threads:[~2026-05-29 14:39 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-28 16:09 [PATCH net-next v4 0/2] " Cedric Jehasse via B4 Relay
2026-05-28 16:09 ` [PATCH net-next v4 1/2] net: dsa: mv88e6xxx: use the hw tx queues Cedric Jehasse via B4 Relay
2026-05-28 16:09 ` [PATCH net-next v4 2/2] net: dsa: mv88e6xxx: add support for credit based shaper Cedric Jehasse via B4 Relay
2026-05-28 23:48 ` Luke Howard
2026-05-29 12:32 ` Cedric Jehasse
2026-05-29 12:45 ` Luke Howard
2026-05-29 13:28 ` Andrew Lunn
2026-05-29 14:32 ` Cedric Jehasse
2026-05-29 14:38 ` Andrew Lunn [this message]
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