linux-kernel - Re: [PATCH net-next v2 5/6] netconsole: resume previously deactivated target

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Message-ID: <t32t7uopvipphrbo7zsnkbayhpj5vgogfcagkt5sumknchmsia@n6znkrsulm4p>
Date: Tue, 23 Sep 2025 05:22:25 -0700
From: Breno Leitao <leitao@...ian.org>
To: Andre Carvalho <asantostc@...il.com>
Cc: Andrew Lunn <andrew+netdev@...n.ch>, 
	"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Shuah Khan <shuah@...nel.org>, 
	Simon Horman <horms@...nel.org>, netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-kselftest@...r.kernel.org
Subject: Re: [PATCH net-next v2 5/6] netconsole: resume previously
 deactivated target

Hello Andre,

On Sun, Sep 21, 2025 at 10:55:45PM +0100, Andre Carvalho wrote:
> Attempt to resume a previously deactivated target when the associated
> interface comes back (NETDEV_UP event is received) by calling
> __netpoll_setup_hold on the device.
> 
> For targets that were initally setup by mac address, their address is
> also compared with the interface address (while still verifying that the
> interface name matches).

For targets that are set by the mac address, they don't necessarily get
np.dev_name populated, do they?

I am double checking netpoll_setup(), and if
is_valid_ether_addr(np->dev_mac), I don't see np.dev_name being
populated.

> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index 59d770bb4baa5f9616b10c0dfb39ed45a4eb7710..96485e979e61e0ed6c850ae3b29f46d529923f2d 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> +/* Attempts to resume logging to a deactivated target. */
> +static void maybe_resume_target(struct netconsole_target *nt,
> +				struct net_device *ndev)
> +{
> +	int ret;
> +
> +	if (strncmp(nt->np.dev_name, ndev->name, IFNAMSIZ))
> +		return;

But here, you expect that np.dev_name is populate, which I suppose it
will fail if the target is binding by np->dev_mac.

Should we also compare that the mac doesn't match before returning?

--breno