CVE-2025-39947

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5e: Harden uplink netdev access against device unbind

The function mlx5_uplink_netdev_get() gets the uplink netdevice

pointer from mdev->mlx5e_res.uplink_netdev. However, the netdevice can

be removed and its pointer cleared when unbound from the mlx5_core.eth

driver. This results in a NULL pointer, causing a kernel panic.

BUG: unable to handle page fault for address: 0000000000001300

at RIP: 0010:mlx5e_vport_rep_load+0x22a/0x270 [mlx5_core]

Call Trace:

<TASK>

mlx5_esw_offloads_rep_load+0x68/0xe0 [mlx5_core]

esw_offloads_enable+0x593/0x910 [mlx5_core]

mlx5_eswitch_enable_locked+0x341/0x420 [mlx5_core]

mlx5_devlink_eswitch_mode_set+0x17e/0x3a0 [mlx5_core]

devlink_nl_eswitch_set_doit+0x60/0xd0

genl_family_rcv_msg_doit+0xe0/0x130

genl_rcv_msg+0x183/0x290

netlink_rcv_skb+0x4b/0xf0

genl_rcv+0x24/0x40

netlink_unicast+0x255/0x380

netlink_sendmsg+0x1f3/0x420

__sock_sendmsg+0x38/0x60

__sys_sendto+0x119/0x180

do_syscall_64+0x53/0x1d0

entry_SYSCALL_64_after_hwframe+0x4b/0x53

Ensure the pointer is valid before use by checking it for NULL. If it

is valid, immediately call netdev_hold() to take a reference, and

preventing the netdevice from being freed while it is in use.