{"id":"CVE-2026-23368","summary":"net: phy: register phy led_triggers during probe to avoid AB-BA deadlock","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: phy: register phy led_triggers during probe to avoid AB-BA deadlock\n\nThere is an AB-BA deadlock when both LEDS_TRIGGER_NETDEV and\nLED_TRIGGER_PHY are enabled:\n\n[ 1362.049207] [\u003c8054e4b8\u003e] led_trigger_register+0x5c/0x1fc             \u003c-- Trying to get lock \"triggers_list_lock\" via down_write(&triggers_list_lock);\n[ 1362.054536] [\u003c80662830\u003e] phy_led_triggers_register+0xd0/0x234\n[ 1362.060329] [\u003c8065e200\u003e] phy_attach_direct+0x33c/0x40c\n[ 1362.065489] [\u003c80651fc4\u003e] phylink_fwnode_phy_connect+0x15c/0x23c\n[ 1362.071480] [\u003c8066ee18\u003e] mtk_open+0x7c/0xba0\n[ 1362.075849] [\u003c806d714c\u003e] __dev_open+0x280/0x2b0\n[ 1362.080384] [\u003c806d7668\u003e] __dev_change_flags+0x244/0x24c\n[ 1362.085598] [\u003c806d7698\u003e] dev_change_flags+0x28/0x78\n[ 1362.090528] [\u003c807150e4\u003e] dev_ioctl+0x4c0/0x654                       \u003c-- Hold lock \"rtnl_mutex\" by calling rtnl_lock();\n[ 1362.094985] [\u003c80694360\u003e] sock_ioctl+0x2f4/0x4e0\n[ 1362.099567] [\u003c802e9c4c\u003e] sys_ioctl+0x32c/0xd8c\n[ 1362.104022] [\u003c80014504\u003e] syscall_common+0x34/0x58\n\nHere LED_TRIGGER_PHY is registering LED triggers during phy_attach\nwhile holding RTNL and then taking triggers_list_lock.\n\n[ 1362.191101] [\u003c806c2640\u003e] register_netdevice_notifier+0x60/0x168      \u003c-- Trying to get lock \"rtnl_mutex\" via rtnl_lock();\n[ 1362.197073] [\u003c805504ac\u003e] netdev_trig_activate+0x194/0x1e4\n[ 1362.202490] [\u003c8054e28c\u003e] led_trigger_set+0x1d4/0x360                 \u003c-- Hold lock \"triggers_list_lock\" by down_read(&triggers_list_lock);\n[ 1362.207511] [\u003c8054eb38\u003e] led_trigger_write+0xd8/0x14c\n[ 1362.212566] [\u003c80381d98\u003e] sysfs_kf_bin_write+0x80/0xbc\n[ 1362.217688] [\u003c8037fcd8\u003e] kernfs_fop_write_iter+0x17c/0x28c\n[ 1362.223174] [\u003c802cbd70\u003e] vfs_write+0x21c/0x3c4\n[ 1362.227712] [\u003c802cc0c4\u003e] ksys_write+0x78/0x12c\n[ 1362.232164] [\u003c80014504\u003e] syscall_common+0x34/0x58\n\nHere LEDS_TRIGGER_NETDEV is being enabled on an LED. It first takes\ntriggers_list_lock and then RTNL. A classical AB-BA deadlock.\n\nphy_led_triggers_registers() does not require the RTNL, it does not\nmake any calls into the network stack which require protection. There\nis also no requirement the PHY has been attached to a MAC, the\ntriggers only make use of phydev state. This allows the call to\nphy_led_triggers_registers() to be placed elsewhere. PHY probe() and\nrelease() don't hold RTNL, so solving the AB-BA deadlock.","modified":"2026-04-14T03:48:46.539423Z","published":"2026-03-25T10:27:49.889Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23368.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/241cd64cf2e32b28ead151b1795cd8fef2b6e482"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2764dcb3c35de4410f642afc62cf979727470575"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c33523b8fd2d4c504ada18cd93f511f2a8f84217"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c6ffc2d2338d325e1edd0c702e3ee623aa5fdc6a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c8dbdc6e380e7e96a51706db3e4b7870d8a9402d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cde2d0b5ab5d03b5b6f17d4f654d8b30ccf36757"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23368.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23368"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"06f502f57d0d7728f9fa0f157ec5e4111ddb98f6"},{"fixed":"c6ffc2d2338d325e1edd0c702e3ee623aa5fdc6a"},{"fixed":"c33523b8fd2d4c504ada18cd93f511f2a8f84217"},{"fixed":"241cd64cf2e32b28ead151b1795cd8fef2b6e482"},{"fixed":"2764dcb3c35de4410f642afc62cf979727470575"},{"fixed":"cde2d0b5ab5d03b5b6f17d4f654d8b30ccf36757"},{"fixed":"c8dbdc6e380e7e96a51706db3e4b7870d8a9402d"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-23368.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.16.0"},{"fixed":"6.1.167"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.130"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.78"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.17"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-23368.json"}}],"schema_version":"1.7.5"}