linux-stable.git/drivers/net/phy/phy_device.c, branch linux-5.10.y

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

2026-04-18T08:30:59+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_get_internal_delay accessing an empty array

2024-03-26T22:21:53+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: prevent stale pointer dereference in phy_init()

2023-07-27T06:44:43+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

2023-03-17T07:45:11+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: phy: fix null-ptr-deref while probe() failed

2022-12-08T10:23:56+00:00

[ Upstream commit 369eb2c9f1f72adbe91e0ea8efb130f0a2ba11a6 ]

I got a null-ptr-deref report as following when doing fault injection test:

BUG: kernel NULL pointer dereference, address: 0000000000000058
Oops: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 PID: 253 Comm: 507-spi-dm9051 Tainted: G    B            N 6.1.0-rc3+
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:klist_put+0x2d/0xd0
Call Trace:
 
 klist_remove+0xf1/0x1c0
 device_release_driver_internal+0x23e/0x2d0
 bus_remove_device+0x1bd/0x240
 device_del+0x357/0x770
 phy_device_remove+0x11/0x30
 mdiobus_unregister+0xa5/0x140
 release_nodes+0x6a/0xa0
 devres_release_all+0xf8/0x150
 device_unbind_cleanup+0x19/0xd0

//probe path:
phy_device_register()
  device_add()

phy_connect
  phy_attach_direct() //set device driver
    probe() //it's failed, driver is not bound
    device_bind_driver() // probe failed, it's not called

//remove path:
phy_device_remove()
  device_del()
    device_release_driver_internal()
      __device_release_driver() //dev->drv is not NULL
        klist_remove() <- knode_driver is not added yet, cause null-ptr-deref

In phy_attach_direct(), after setting the 'dev->driver', probe() fails,
device_bind_driver() is not called, so the knode_driver->n_klist is not
set, then it causes null-ptr-deref in __device_release_driver() while
deleting device. Fix this by setting dev->driver to NULL in the error
path in phy_attach_direct().

Fixes: e13934563db0 ("[PATCH] PHY Layer fixup")
Signed-off-by: Yang Yingliang 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

phylib: fix potential use-after-free

2022-02-01T16:25:45+00:00

[ Upstream commit cbda1b16687580d5beee38273f6241ae3725960c ]

Commit bafbdd527d56 ("phylib: Add device reset GPIO support") added call
to phy_device_reset(phydev) after the put_device() call in phy_detach().

The comment before the put_device() call says that the phydev might go
away with put_device().

Fix potential use-after-free by calling phy_device_reset() before
put_device().

Fixes: bafbdd527d56 ("phylib: Add device reset GPIO support")
Signed-off-by: Marek Behún 
Reviewed-by: Andrew Lunn 
Link: https://lore.kernel.org/r/20220119162748.32418-1-kabel@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: phy: introduce phydev->port

2021-03-30T12:32:05+00:00

[ Upstream commit 4217a64e18a1647a0dbc68cb3169a5a06f054ec8 ]

At the moment, PORT_MII is reported in the ethtool ops. This is odd
because it is an interface between the MAC and the PHY and no external
port. Some network card drivers will overwrite the port to twisted pair
or fiber, though. Even worse, the MDI/MDIX setting is only used by
ethtool if the port is twisted pair.

Set the port to PORT_TP by default because most PHY drivers are copper
ones. If there is fibre support and it is enabled, the PHY driver will
set it to PORT_FIBRE.

This will change reporting PORT_MII to either PORT_TP or PORT_FIBRE;
except for the genphy fallback driver.

Suggested-by: Andrew Lunn 
Signed-off-by: Michael Walle 
Reviewed-by: Florian Fainelli 
Reviewed-by: Andrew Lunn 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: phy: make mdio_bus_phy_suspend/resume as __maybe_unused

2021-03-17T16:06:17+00:00

commit 7f654157f0aefba04cd7f6297351c87b76b47b89 upstream.

When CONFIG_PM_SLEEP is disabled, the compiler warns about unused
functions:

drivers/net/phy/phy_device.c:273:12: error: unused function 'mdio_bus_phy_suspend' [-Werror,-Wunused-function]
static int mdio_bus_phy_suspend(struct device *dev)
drivers/net/phy/phy_device.c:293:12: error: unused function 'mdio_bus_phy_resume' [-Werror,-Wunused-function]
static int mdio_bus_phy_resume(struct device *dev)

The logic is intentional, so just mark these two as __maybe_unused
and remove the incorrect #ifdef.

Fixes: 4c0d2e96ba05 ("net: phy: consider that suspend2ram may cut off PHY power")
Signed-off-by: Arnd Bergmann 
Reviewed-by: Andrew Lunn 
Link: https://lore.kernel.org/r/20210225145748.404410-1-arnd@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: phy: consider that suspend2ram may cut off PHY power

2021-03-04T10:37:31+00:00

[ Upstream commit 4c0d2e96ba055bd8911bb8287def4f8ebbad15b6 ]

Claudiu reported that on his system S2R cuts off power to the PHY and
after resuming certain PHY settings are lost. The PM folks confirmed
that cutting off power to selected components in S2R is a valid case.
Therefore resuming from S2R, same as from hibernation, has to assume
that the PHY has power-on defaults. As a consequence use the restore
callback also as resume callback.
In addition make sure that the interrupt configuration is restored.
Let's do this in phy_init_hw() and ensure that after this call
actual interrupt configuration is in sync with phydev->interrupts.
Currently, if interrupt was enabled before hibernation, we would
resume with interrupt disabled because that's the power-on default.

This fix applies cleanly only after the commit marked as fixed.

I don't have an affected system, therefore change is compile-tested
only.

[0] https://lore.kernel.org/netdev/1610120754-14331-1-git-send-email-claudiu.beznea@microchip.com/

Fixes: 611d779af7ca ("net: phy: fix MDIO bus PM PHY resuming")
Reported-by: Claudiu Beznea 
Signed-off-by: Heiner Kallweit 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: phy: Avoid NPD upon phy_detach() when driver is unbound

2020-09-17T23:55:35+00:00

If we have unbound the PHY driver prior to calling phy_detach() (often
via phy_disconnect()) then we can cause a NULL pointer de-reference
accessing the driver owner member. The steps to reproduce are:

echo unimac-mdio-0:01 > /sys/class/net/eth0/phydev/driver/unbind
ip link set eth0 down

Fixes: cafe8df8b9bc ("net: phy: Fix lack of reference count on PHY driver")
Signed-off-by: Florian Fainelli 
Reviewed-by: Andrew Lunn 
Signed-off-by: David S. Miller