target/linux/generic/backport-5.15/792-02-v6.0-net-phylink-fix-NULL-pl-pcs-dereference-during-phyli.patch

   1 From b7d78b46d5e8dc77c656c13885d31e931923b915 Mon Sep 17 00:00:00 2001
   2 From: Vladimir Oltean <vladimir.oltean@nxp.com>
   3 Date: Wed, 29 Jun 2022 22:33:58 +0300
   4 Subject: [PATCH] net: phylink: fix NULL pl->pcs dereference during
   5  phylink_pcs_poll_start
   6
   7 The current link mode of the phylink instance may not require an
   8 attached PCS. However, phylink_major_config() unconditionally
   9 dereferences this potentially NULL pointer when restarting the link poll
  10 timer, which will panic the kernel.
  11
  12 Fix the problem by checking whether a PCS exists in phylink_pcs_poll_start(),
  13 otherwise do nothing. The code prior to the blamed patch also only
  14 looked at pcs->poll within an "if (pcs)" block.
  15
  16 Fixes: bfac8c490d60 ("net: phylink: disable PCS polling over major configuration")
  17 Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
  18 Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
  19 Tested-by: Gerhard Engleder <gerhard@engleder-embedded.com>
  20 Tested-by: Michael Walle <michael@walle.cc> # on kontron-kbox-a-230-ls
  21 Tested-by: Nicolas Ferre <nicolas.ferre@microchip.com> # on sam9x60ek
  22 Link: https://lore.kernel.org/r/20220629193358.4007923-1-vladimir.oltean@nxp.com
  23 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  24 ---
  25  drivers/net/phy/phylink.c | 2 +-
  26  1 file changed, 1 insertion(+), 1 deletion(-)
  27
  28 --- a/drivers/net/phy/phylink.c
  29 +++ b/drivers/net/phy/phylink.c
  30 @@ -764,7 +764,7 @@ static void phylink_pcs_poll_stop(struct
  31
  32  static void phylink_pcs_poll_start(struct phylink *pl)
  33  {
  34 -       if (pl->pcs->poll && pl->cfg_link_an_mode == MLO_AN_INBAND)
  35 +       if (pl->pcs && pl->pcs->poll && pl->cfg_link_an_mode == MLO_AN_INBAND)
  36                 mod_timer(&pl->link_poll, jiffies + HZ);
  37  }
  38