kernel/linux.git/drivers/net/phy/phy_device.c, branch v6.1.168

net: phy: fix phy_uses_state_machine()

2026-04-11T12:16:38+00:00

[ Upstream commit e0d1c55501d377163eb57feed863777ed1c973ad ] The blamed commit changed the conditions which phylib uses to stop and start the state machine in the suspend and resume paths, and while improving it, has caused two issues. The original code used this test: phydev->attached_dev && phydev->adjust_link and if true, the paths would handle the PHY state machine. This test evaluates true for normal drivers that are using phylib directly while the PHY is attached to the network device, but false in all other cases, which include the following cases: - when the PHY has never been attached to a network device. - when the PHY has been detached from a network device (as phy_detach() sets phydev->attached_dev to NULL, phy_disconnect() calls phy_detach() and additionally sets phydev->adjust_link NULL.) - when phylink is using the driver (as phydev->adjust_link is NULL.) Only the third case was incorrect, and the blamed commit attempted to fix this by changing this test to (simplified for brevity, see phy_uses_state_machine()): phydev->phy_link_change == phy_link_change ? phydev->attached_dev && phydev->adjust_link : true However, this also incorrectly evaluates true in the first two cases. Fix the first case by ensuring that phy_uses_state_machine() returns false when phydev->phy_link_change is NULL. Fix the second case by ensuring that phydev->phy_link_change is set to NULL when phy_detach() is called. Reported-by: Xu Yang Link: https://lore.kernel.org/r/20250806082931.3289134-1-xu.yang_2@nxp.com Fixes: fc75ea20ffb4 ("net: phy: allow MDIO bus PM ops to start/stop state machine for phylink-controlled PHY") Signed-off-by: Russell King (Oracle) Reviewed-by: Vladimir Oltean Link: https://patch.msgid.link/E1uvMEz-00000003Aoe-3qWe@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski Signed-off-by: Rajani Kantha <681739313@139.com> Signed-off-by: Greg Kroah-Hartman

net: phy: allow MDIO bus PM ops to start/stop state machine for phylink-controlled PHY

2026-04-11T12:16:37+00:00

[ Upstream commit fc75ea20ffb452652f0d4033f38fe88d7cfdae35 ] DSA has 2 kinds of drivers: 1. Those who call dsa_switch_suspend() and dsa_switch_resume() from their device PM ops: qca8k-8xxx, bcm_sf2, microchip ksz 2. Those who don't: all others. The above methods should be optional. For type 1, dsa_switch_suspend() calls dsa_user_suspend() -> phylink_stop(), and dsa_switch_resume() calls dsa_user_resume() -> phylink_start(). These seem good candidates for setting mac_managed_pm = true because that is essentially its definition [1], but that does not seem to be the biggest problem for now, and is not what this change focuses on. Talking strictly about the 2nd category of DSA drivers here (which do not have MAC managed PM, meaning that for their attached PHYs, mdio_bus_phy_suspend() and mdio_bus_phy_resume() should run in full), I have noticed that the following warning from mdio_bus_phy_resume() is triggered: WARN_ON(phydev->state != PHY_HALTED && phydev->state != PHY_READY && phydev->state != PHY_UP); because the PHY state machine is running. It's running as a result of a previous dsa_user_open() -> ... -> phylink_start() -> phy_start() having been initiated by the user. The previous mdio_bus_phy_suspend() was supposed to have called phy_stop_machine(), but it didn't. So this is why the PHY is in state PHY_NOLINK by the time mdio_bus_phy_resume() runs. mdio_bus_phy_suspend() did not call phy_stop_machine() because for phylink, the phydev->adjust_link function pointer is NULL. This seems a technicality introduced by commit fddd91016d16 ("phylib: fix PAL state machine restart on resume"). That commit was written before phylink existed, and was intended to avoid crashing with consumer drivers which don't use the PHY state machine - phylink always does, when using a PHY. But phylink itself has historically not been developed with suspend/resume in mind, and apparently not tested too much in that scenario, allowing this bug to exist unnoticed for so long. Plus, prior to the WARN_ON(), it would have likely been invisible. This issue is not in fact restricted to type 2 DSA drivers (according to the above ad-hoc classification), but can be extrapolated to any MAC driver with phylink and MDIO-bus-managed PHY PM ops. DSA is just where the issue was reported. Assuming mac_managed_pm is set correctly, a quick search indicates the following other drivers might be affected: $ grep -Zlr PHYLINK_NETDEV drivers/ | xargs -0 grep -L mac_managed_pm drivers/net/ethernet/atheros/ag71xx.c drivers/net/ethernet/microchip/sparx5/sparx5_main.c drivers/net/ethernet/microchip/lan966x/lan966x_main.c drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c drivers/net/ethernet/freescale/dpaa/dpaa_eth.c drivers/net/ethernet/freescale/ucc_geth.c drivers/net/ethernet/freescale/enetc/enetc_pf_common.c drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c drivers/net/ethernet/marvell/mvneta.c drivers/net/ethernet/marvell/prestera/prestera_main.c drivers/net/ethernet/mediatek/mtk_eth_soc.c drivers/net/ethernet/altera/altera_tse_main.c drivers/net/ethernet/wangxun/txgbe/txgbe_phy.c drivers/net/ethernet/meta/fbnic/fbnic_phylink.c drivers/net/ethernet/tehuti/tn40_phy.c drivers/net/ethernet/mscc/ocelot_net.c Make the existing conditions dependent on the PHY device having a phydev->phy_link_change() implementation equal to the default phy_link_change() provided by phylib. Otherwise, we implicitly know that the phydev has the phylink-provided phylink_phy_change() callback, and when phylink is used, the PHY state machine always needs to be stopped/ started on the suspend/resume path. The code is structured as such that if phydev->phy_link_change() is absent, it is a matter of time until the kernel will crash - no need to further complicate the test. Thus, for the situation where the PM is not managed by the MAC, we will make the MDIO bus PM ops treat identically the phylink-controlled PHYs with the phylib-controlled PHYs where an adjust_link() callback is supplied. In both cases, the MDIO bus PM ops should stop and restart the PHY state machine. [1] https://lore.kernel.org/netdev/Z-1tiW9zjcoFkhwc@shell.armlinux.org.uk/ Fixes: 744d23c71af3 ("net: phy: Warn about incorrect mdio_bus_phy_resume() state") Reported-by: Wei Fang Tested-by: Wei Fang Signed-off-by: Vladimir Oltean Link: https://patch.msgid.link/20250407094042.2155633-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski Signed-off-by: Rajani Kantha <681739313@139.com> Signed-off-by: Greg Kroah-Hartman

net: phy: move phy_link_change() prior to mdio_bus_phy_may_suspend()

2026-04-11T12:16:37+00:00

[ Upstream commit f40a673d6b4a128fe95dd9b8c3ed02da50a6a862 ] In an upcoming change, mdio_bus_phy_may_suspend() will need to distinguish a phylib-based PHY client from a phylink PHY client. For that, it will need to compare the phydev->phy_link_change() function pointer with the eponymous phy_link_change() provided by phylib. To avoid forward function declarations, the default PHY link state change method should be moved upwards. There is no functional change associated with this patch, it is only to reduce the noise from a real bug fix. Signed-off-by: Vladimir Oltean Reviewed-by: Russell King (Oracle) Link: https://patch.msgid.link/20250407093900.2155112-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski [ Minor context change fixed ] Signed-off-by: Rajani Kantha <681739313@139.com> Signed-off-by: Greg Kroah-Hartman

net: phy: register phy led_triggers during probe to avoid AB-BA deadlock

2026-03-25T10:03:14+00:00

[ Upstream commit c8dbdc6e380e7e96a51706db3e4b7870d8a9402d ] There is an AB-BA deadlock when both LEDS_TRIGGER_NETDEV and LED_TRIGGER_PHY are enabled: [ 1362.049207] [<8054e4b8>] led_trigger_register+0x5c/0x1fc <-- Trying to get lock "triggers_list_lock" via down_write(&triggers_list_lock); [ 1362.054536] [<80662830>] phy_led_triggers_register+0xd0/0x234 [ 1362.060329] [<8065e200>] phy_attach_direct+0x33c/0x40c [ 1362.065489] [<80651fc4>] phylink_fwnode_phy_connect+0x15c/0x23c [ 1362.071480] [<8066ee18>] mtk_open+0x7c/0xba0 [ 1362.075849] [<806d714c>] __dev_open+0x280/0x2b0 [ 1362.080384] [<806d7668>] __dev_change_flags+0x244/0x24c [ 1362.085598] [<806d7698>] dev_change_flags+0x28/0x78 [ 1362.090528] [<807150e4>] dev_ioctl+0x4c0/0x654 <-- Hold lock "rtnl_mutex" by calling rtnl_lock(); [ 1362.094985] [<80694360>] sock_ioctl+0x2f4/0x4e0 [ 1362.099567] [<802e9c4c>] sys_ioctl+0x32c/0xd8c [ 1362.104022] [<80014504>] 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] [<806c2640>] register_netdevice_notifier+0x60/0x168 <-- Trying to get lock "rtnl_mutex" via rtnl_lock(); [ 1362.197073] [<805504ac>] netdev_trig_activate+0x194/0x1e4 [ 1362.202490] [<8054e28c>] led_trigger_set+0x1d4/0x360 <-- Hold lock "triggers_list_lock" by down_read(&triggers_list_lock); [ 1362.207511] [<8054eb38>] led_trigger_write+0xd8/0x14c [ 1362.212566] [<80381d98>] sysfs_kf_bin_write+0x80/0xbc [ 1362.217688] [<8037fcd8>] kernfs_fop_write_iter+0x17c/0x28c [ 1362.223174] [<802cbd70>] vfs_write+0x21c/0x3c4 [ 1362.227712] [<802cc0c4>] ksys_write+0x78/0x12c [ 1362.232164] [<80014504>] 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. Reported-by: Shiji Yang Closes: https://lore.kernel.org/all/OS7PR01MB13602B128BA1AD3FA38B6D1FFBC69A@OS7PR01MB13602.jpnprd01.prod.outlook.com/ Fixes: 06f502f57d0d ("leds: trigger: Introduce a NETDEV trigger") Cc: stable@vger.kernel.org Signed-off-by: Andrew Lunn Tested-by: Shiji Yang Link: https://patch.msgid.link/20260222152601.1978655-1-andrew@lunn.ch Signed-off-by: Paolo Abeni [ dropped `is_on_sfp_module` guards and `CONFIG_PHYLIB_LEDS`/`of_phy_leds` logic ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

net: phy: fix phy_read_poll_timeout argument type in genphy_loopback

2024-03-26T22:21:00+00:00

[ Upstream commit 32fa4366cc4da1c97b725a0066adf43c6b298f37 ] read_poll_timeout inside phy_read_poll_timeout can set val negative in some cases (for example, __mdiobus_read inside phy_read can return -EOPNOTSUPP). Supposedly, commit 4ec732951702 ("net: phylib: fix phy_read*_poll_timeout()") should fix problems with wrong-signed vals, but I do not see how as val is sent to phy_read as is and __val = phy_read (not val) is checked for sign. Change val type for signed to allow better error handling as done in other phy_read_poll_timeout callers. This will not fix any error handling by itself, but allows, for example, to modify cond with appropriate sign check or check resulting val separately. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 014068dcb5b1 ("net: phy: genphy_loopback: add link speed configuration") Signed-off-by: Nikita Kiryushin Reviewed-by: Russell King (Oracle) Link: https://lore.kernel.org/r/20240315175052.8049-1-kiryushin@ancud.ru Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: phy: fix phy_get_internal_delay accessing an empty array

2024-03-26T22:20:41+00:00

[ Upstream commit 4469c0c5b14a0919f5965c7ceac96b523eb57b79 ] The phy_get_internal_delay function could try to access to an empty array in the case that the driver is calling phy_get_internal_delay without defining delay_values and rx-internal-delay-ps or tx-internal-delay-ps is defined to 0 in the device-tree. This will lead to "unable to handle kernel NULL pointer dereference at virtual address 0". To avoid this kernel oops, the test should be delay >= 0. As there is already delay < 0 test just before, the test could only be size == 0. Fixes: 92252eec913b ("net: phy: Add a helper to return the index for of the internal delay") Co-developed-by: Enguerrand de Ribaucourt Signed-off-by: Enguerrand de Ribaucourt Signed-off-by: Kévin L'hôpital Reviewed-by: Russell King (Oracle) Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: phy: fix IRQ-based wake-on-lan over hibernate / power off

2023-08-23T15:52:33+00:00

[ Upstream commit cc941e548bffc01b5816b4edc5cb432a137a58b3 ] Uwe reports: "Most PHYs signal WoL using an interrupt. So disabling interrupts [at shutdown] breaks WoL at least on PHYs covered by the marvell driver." Discussing with Ioana, the problem which was trying to be solved was: "The board in question is a LS1021ATSN which has two AR8031 PHYs that share an interrupt line. In case only one of the PHYs is probed and there are pending interrupts on the PHY#2 an IRQ storm will happen since there is no entity to clear the interrupt from PHY#2's registers. PHY#1's driver will get stuck in .handle_interrupt() indefinitely." Further confirmation that "the two AR8031 PHYs are on the same MDIO bus." With WoL using interrupts to wake the system, in such a case, the system will begin booting with an asserted interrupt. Thus, we need to cope with an interrupt asserted during boot. Solve this instead by disabling interrupts during PHY probe. This will ensure in Ioana's situation that both PHYs of the same type sharing an interrupt line on a common MDIO bus will have their interrupt outputs disabled when the driver probes the device, but before we hook in any interrupt handlers - thus avoiding the interrupt storm. A better fix would be for platform firmware to disable the interrupting devices at source during boot, before control is handed to the kernel. Fixes: e2f016cf7751 ("net: phy: add a shutdown procedure") Link: 20230804071757.383971-1-u.kleine-koenig@pengutronix.de Reported-by: Uwe Kleine-König Signed-off-by: Russell King (Oracle) Reviewed-by: Andrew Lunn Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: phy: prevent stale pointer dereference in phy_init()

2023-07-27T06:50:49+00:00

[ Upstream commit 1c613beaf877c0c0d755853dc62687e2013e55c4 ] mdio_bus_init() and phy_driver_register() both have error paths, and if those are ever hit, ethtool will have a stale pointer to the phy_ethtool_phy_ops stub structure, which references memory from a module that failed to load (phylib). It is probably hard to force an error in this code path even manually, but the error teardown path of phy_init() should be the same as phy_exit(), which is now simply not the case. Fixes: 55d8f053ce1b ("net: phy: Register ethtool PHY operations") Link: https://lore.kernel.org/netdev/ZLaiJ4G6TaJYGJyU@shell.armlinux.org.uk/ Suggested-by: Russell King (Oracle) Signed-off-by: Vladimir Oltean Link: https://lore.kernel.org/r/20230720000231.1939689-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: phylib: get rid of unnecessary locking

2023-03-17T07:50:25+00:00

[ Upstream commit f4b47a2e9463950df3e7c8b70e017877c1d4eb11 ] The locking in phy_probe() and phy_remove() does very little to prevent any races with e.g. phy_attach_direct(), but instead causes lockdep ABBA warnings. Remove it. ====================================================== WARNING: possible circular locking dependency detected 6.2.0-dirty #1108 Tainted: G W E ------------------------------------------------------ ip/415 is trying to acquire lock: ffff5c268f81ef50 (&dev->lock){+.+.}-{3:3}, at: phy_attach_direct+0x17c/0x3a0 [libphy] but task is already holding lock: ffffaef6496cb518 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x154/0x560 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (rtnl_mutex){+.+.}-{3:3}: __lock_acquire+0x35c/0x6c0 lock_acquire.part.0+0xcc/0x220 lock_acquire+0x68/0x84 __mutex_lock+0x8c/0x414 mutex_lock_nested+0x34/0x40 rtnl_lock+0x24/0x30 sfp_bus_add_upstream+0x34/0x150 phy_sfp_probe+0x4c/0x94 [libphy] mv3310_probe+0x148/0x184 [marvell10g] phy_probe+0x8c/0x200 [libphy] call_driver_probe+0xbc/0x15c really_probe+0xc0/0x320 __driver_probe_device+0x84/0x120 driver_probe_device+0x44/0x120 __device_attach_driver+0xc4/0x160 bus_for_each_drv+0x80/0xe0 __device_attach+0xb0/0x1f0 device_initial_probe+0x1c/0x2c bus_probe_device+0xa4/0xb0 device_add+0x360/0x53c phy_device_register+0x60/0xa4 [libphy] fwnode_mdiobus_phy_device_register+0xc0/0x190 [fwnode_mdio] fwnode_mdiobus_register_phy+0x160/0xd80 [fwnode_mdio] of_mdiobus_register+0x140/0x340 [of_mdio] orion_mdio_probe+0x298/0x3c0 [mvmdio] platform_probe+0x70/0xe0 call_driver_probe+0x34/0x15c really_probe+0xc0/0x320 __driver_probe_device+0x84/0x120 driver_probe_device+0x44/0x120 __driver_attach+0x104/0x210 bus_for_each_dev+0x78/0xdc driver_attach+0x2c/0x3c bus_add_driver+0x184/0x240 driver_register+0x80/0x13c __platform_driver_register+0x30/0x3c xt_compat_calc_jump+0x28/0xa4 [x_tables] do_one_initcall+0x50/0x1b0 do_init_module+0x50/0x1fc load_module+0x684/0x744 __do_sys_finit_module+0xc4/0x140 __arm64_sys_finit_module+0x28/0x34 invoke_syscall+0x50/0x120 el0_svc_common.constprop.0+0x6c/0x1b0 do_el0_svc+0x34/0x44 el0_svc+0x48/0xf0 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x1a0/0x1a4 -> #0 (&dev->lock){+.+.}-{3:3}: check_prev_add+0xb4/0xc80 validate_chain+0x414/0x47c __lock_acquire+0x35c/0x6c0 lock_acquire.part.0+0xcc/0x220 lock_acquire+0x68/0x84 __mutex_lock+0x8c/0x414 mutex_lock_nested+0x34/0x40 phy_attach_direct+0x17c/0x3a0 [libphy] phylink_fwnode_phy_connect.part.0+0x70/0xe4 [phylink] phylink_fwnode_phy_connect+0x48/0x60 [phylink] mvpp2_open+0xec/0x2e0 [mvpp2] __dev_open+0x104/0x214 __dev_change_flags+0x1d4/0x254 dev_change_flags+0x2c/0x7c do_setlink+0x254/0xa50 __rtnl_newlink+0x430/0x514 rtnl_newlink+0x58/0x8c rtnetlink_rcv_msg+0x17c/0x560 netlink_rcv_skb+0x64/0x150 rtnetlink_rcv+0x20/0x30 netlink_unicast+0x1d4/0x2b4 netlink_sendmsg+0x1a4/0x400 ____sys_sendmsg+0x228/0x290 ___sys_sendmsg+0x88/0xec __sys_sendmsg+0x70/0xd0 __arm64_sys_sendmsg+0x2c/0x40 invoke_syscall+0x50/0x120 el0_svc_common.constprop.0+0x6c/0x1b0 do_el0_svc+0x34/0x44 el0_svc+0x48/0xf0 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x1a0/0x1a4 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rtnl_mutex); lock(&dev->lock); lock(rtnl_mutex); lock(&dev->lock); *** DEADLOCK *** Fixes: 298e54fa810e ("net: phy: add core phylib sfp support") Reported-by: Marc Zyngier Signed-off-by: Russell King (Oracle) Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: mdiobus: fix unbalanced node reference count

2022-11-29T02:10:25+00:00

I got the following report while doing device(mscc-miim) load test with CONFIG_OF_UNITTEST and CONFIG_OF_DYNAMIC enabled: OF: ERROR: memory leak, expected refcount 1 instead of 2, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node /spi/soc@0/mdio@7107009c/ethernet-phy@0 If the 'fwnode' is not an acpi node, the refcount is get in fwnode_mdiobus_phy_device_register(), but it has never been put when the device is freed in the normal path. So call fwnode_handle_put() in phy_device_release() to avoid leak. If it's an acpi node, it has never been get, but it's put in the error path, so call fwnode_handle_get() before phy_device_register() to keep get/put operation balanced. Fixes: bc1bee3b87ee ("net: mdiobus: Introduce fwnode_mdiobus_register_phy()") Signed-off-by: Yang Yingliang Reviewed-by: Andrew Lunn Link: https://lore.kernel.org/r/20221124150130.609420-1-yangyingliang@huawei.com Signed-off-by: Jakub Kicinski