Subject: Re: [PATCH net-next] net: phylink: fix NULL pl->pcs dereference during phylink_pcs_poll_start

From: "Russell King (Oracle)" <[email-masked]>
Date: Wed, 29 Jun 2022 20:42:02 +0100

On Wed, Jun 29, 2022 at 10:33:58PM +0300, Vladimir Oltean wrote:
> The current link mode of the phylink instance may not require an
> attached PCS. However, phylink_major_config() unconditionally
> dereferences this potentially NULL pointer when restarting the link poll
> timer, which will panic the kernel.
> 
> Fix the problem by checking whether a PCS exists in phylink_pcs_poll_start(),
> otherwise do nothing. The code prior to the blamed patch also only
> looked at pcs->poll within an "if (pcs)" block.
> 
> Fixes: bfac8c490d60 ("net: phylink: disable PCS polling over major configuration")
> Signed-off-by: Vladimir Oltean <[email-masked]>

Thanks.

Reviewed-by: Russell King (Oracle) <[email-masked]>

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