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

On 29.06.22 21:42, Russell King (Oracle) wrote:

On Wed, Jun 29, 2022 at 10:33:58PM +0300, Vladimir Oltean wrote:

quoted

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 <vladimir.oltean@nxp.com>

Thanks.

Reviewed-by: Russell King (Oracle) <redacted>

Fixes the problem on my side.

Tested-by: Gerhard Engleder <redacted>