TNCVE-2026-23368

In the Linux kernel, the following vulnerability has been resolved: net: phy: register phy led_triggers during probe to avoid AB-BA deadlock There is an AB-BA deadlock when both LEDS_TRIGGER_NETDEV and LED_TRIGGER_PHY are enabled: [ 1362.049207] [ ] led_trigger_register+0x5c/0x1fc ] phy_led_triggers_register+0xd0/0x234 [ 1362.060329] [ ] phy_attach_direct+0x33c/0x40c [ 1362.065489] [ ] phylink_fwnode_phy_connect+0x15c/0x23c [ 1362.071480] [ ] mtk_open+0x7c/0xba0 [ 1362.075849] [ ] __dev_open+0x280/0x2b0 [ 1362.080384] [ ] __dev_change_flags+0x244/0x24c [ 1362.085598] [ ] dev_change_flags+0x28/0x78 [ 1362.090528] [ ] dev_ioctl+0x4c0/0x654 ] sock_ioctl+0x2f4/0x4e0 [ 1362.099567] [ ] sys_ioctl+0x32c/0xd8c [ 1362.104022] [ ] syscall_common+0x34/0x58 Here LED_TRIGGER_PHY is registering LED triggers during phy_attach while holding RTNL and then taking triggers_list_lock. [ 1362.191101] [ ] register_netdevice_notifier+0x60/0x168 ] netdev_trig_activate+0x194/0x1e4 [ 1362.202490] [ ] led_trigger_set+0x1d4/0x360 ] led_trigger_write+0xd8/0x14c [ 1362.212566] [ ] sysfs_kf_bin_write+0x80/0xbc [ 1362.217688] [ ] kernfs_fop_write_iter+0x17c/0x28c [ 1362.223174] [ ] vfs_write+0x21c/0x3c4 [ 1362.227712] [ ] ksys_write+0x78/0x12c [ 1362.232164] [ ] syscall_common+0x34/0x58 Here LEDS_TRIGGER_NETDEV is being enabled on an LED. It first takes triggers_list_lock and then RTNL. A classical AB-BA deadlock. phy_led_triggers_registers() does not require the RTNL, it does not make any calls into the network stack which require protection. There is also no requirement the PHY has been attached to a MAC, the triggers only make use of phydev state. This allows the call to phy_led_triggers_registers() to be placed elsewhere. PHY probe() and release() don't hold RTNL, so solving the AB-BA deadlock.