7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nicolai Buchwitz [ Upstream commit 19419faf58dfe5bcc8a9e60e622976c5f8e3ddc1 ] The Rx ring priv and index are only set in bcmgenet_init_rx_ring(), which runs at open. Setting the Rx coalescing parameters on an interface that was never opened, e.g. "ethtool -C eth0 rx-usecs 50", dereferences a NULL ring->priv. The oops happens with RTNL held, so networking stays stuck until a reboot: Unable to handle kernel paging request at virtual address 0000000000002788 pc : bcmgenet_set_rx_coalesce.isra.0+0x10/0x88 lr : bcmgenet_set_coalesce+0xe8/0x180 Call trace: bcmgenet_set_rx_coalesce.isra.0+0x10/0x88 (P) __ethnl_set_coalesce.isra.0+0x490/0x570 ethnl_set_coalesce+0x48/0xc0 ethnl_default_set_doit+0xf4/0x230 genl_family_rcv_msg_doit+0xe8/0x160 genl_rcv_msg+0x220/0x2a0 netlink_rcv_skb+0x68/0x140 genl_rcv+0x40/0x60 netlink_unicast+0x338/0x3c0 netlink_sendmsg+0x19c/0x3f8 __sock_sendmsg+0x64/0xc0 __sys_sendto+0x124/0x198 __arm64_sys_sendto+0x30/0x48 Set priv and index at probe. Writing the registers while the interface is down is harmless because open resets the MAC and bcmgenet_init_rx_coalesce() reapplies the stored values. It was observed on a Raspberry Pi CM4, but should apply to all other genet devices. Fixes: 9f4ca05827a2 ("net: bcmgenet: Add support for adaptive RX coalescing") Signed-off-by: Nicolai Buchwitz Reviewed-by: Florian Fainelli Link: https://patch.msgid.link/20260928105642.856210-1-nb@tipi-net.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/broadcom/genet/bcmgenet.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c index f725d26e6020f..e8908916558b1 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c @@ -4151,8 +4151,11 @@ static int bcmgenet_probe(struct platform_device *pdev) netif_set_real_num_rx_queues(priv->dev, priv->hw_params->rx_queues + 1); /* Set default coalescing parameters */ - for (i = 0; i <= priv->hw_params->rx_queues; i++) + for (i = 0; i <= priv->hw_params->rx_queues; i++) { + priv->rx_rings[i].priv = priv; + priv->rx_rings[i].index = i; priv->rx_rings[i].rx_max_coalesced_frames = 1; + } /* Initialize u64 stats seq counter for 32bit machines */ for (i = 0; i <= GENET_MAX_MQ_CNT; i++) { -- 2.53.0