netdev - Re: [PATCH net-next v2 1/3] net: add check for current MAC address in dev_set_mac

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Message-ID: <20230620085919.497c3a03@kernel.org>
Date: Tue, 20 Jun 2023 08:59:19 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Gal Pressman <gal@...dia.com>
Cc: Piotr Gardocki <piotrx.gardocki@...el.com>, netdev@...r.kernel.org,
 intel-wired-lan@...ts.osuosl.org, przemyslaw.kitszel@...el.com,
 michal.swiatkowski@...ux.intel.com, pmenzel@...gen.mpg.de,
 maciej.fijalkowski@...el.com, anthony.l.nguyen@...el.com,
 simon.horman@...igine.com, aleksander.lobakin@...el.com
Subject: Re: [PATCH net-next v2 1/3] net: add check for current MAC address
 in dev_set_mac_address

On Tue, 20 Jun 2023 13:42:14 +0300 Gal Pressman wrote:
> > I checked it, you're right. When the addr_assign_type is PERM or RANDOM
> > and user or some driver sets the same MAC address the type doesn't change
> > to NET_ADDR_SET. In my testing I didn't notice issues with that, but I'm
> > sure there are cases I didn't cover. Did you discover any useful cases
> > that broke after this patch or did you just notice it in code?  
> 
> This behavior change was caught in our regression tests.

Why was the regression test written this way?

I guess we won't flip it back to PERM if user sets a completely
different address temporarily and then back to PERM - so for consistency
going to SET even when the addr doesn't change may be reasonable.

Piotr, you'll need to send a new followup patch on top of net-next.