* FAILED: patch "[PATCH] net: phy: register phy led_triggers during probe to avoid" failed to apply to 6.1-stable tree
@ 2026-03-09 10:21 gregkh
2026-03-09 13:50 ` [PATCH 6.1.y] net: phy: register phy led_triggers during probe to avoid AB-BA deadlock Sasha Levin
0 siblings, 1 reply; 2+ messages in thread
From: gregkh @ 2026-03-09 10:21 UTC (permalink / raw)
To: andrew, pabeni, yangshiji66; +Cc: stable
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x c8dbdc6e380e7e96a51706db3e4b7870d8a9402d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026030935-operation-badass-b1bc@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From c8dbdc6e380e7e96a51706db3e4b7870d8a9402d Mon Sep 17 00:00:00 2001
From: Andrew Lunn <andrew@lunn.ch>
Date: Sun, 22 Feb 2026 16:26:01 +0100
Subject: [PATCH] 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] [<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 <yangshiji66@outlook.com>
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 <andrew@lunn.ch>
Tested-by: Shiji Yang <yangshiji66@outlook.com>
Link: https://patch.msgid.link/20260222152601.1978655-1-andrew@lunn.ch
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 9b8eaac63b90..cbb4af604aa5 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1866,8 +1866,6 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
goto error;
phy_resume(phydev);
- if (!phydev->is_on_sfp_module)
- phy_led_triggers_register(phydev);
/**
* If the external phy used by current mac interface is managed by
@@ -1982,9 +1980,6 @@ void phy_detach(struct phy_device *phydev)
phydev->phy_link_change = NULL;
phydev->phylink = NULL;
- if (!phydev->is_on_sfp_module)
- phy_led_triggers_unregister(phydev);
-
if (phydev->mdio.dev.driver)
module_put(phydev->mdio.dev.driver->owner);
@@ -3778,16 +3773,27 @@ static int phy_probe(struct device *dev)
/* Set the state to READY by default */
phydev->state = PHY_READY;
+ /* Register the PHY LED triggers */
+ if (!phydev->is_on_sfp_module)
+ phy_led_triggers_register(phydev);
+
/* Get the LEDs from the device tree, and instantiate standard
* LEDs for them.
*/
- if (IS_ENABLED(CONFIG_PHYLIB_LEDS) && !phy_driver_is_genphy(phydev))
+ if (IS_ENABLED(CONFIG_PHYLIB_LEDS) && !phy_driver_is_genphy(phydev)) {
err = of_phy_leds(phydev);
+ if (err)
+ goto out;
+ }
+
+ return 0;
out:
+ if (!phydev->is_on_sfp_module)
+ phy_led_triggers_unregister(phydev);
+
/* Re-assert the reset signal on error */
- if (err)
- phy_device_reset(phydev, 1);
+ phy_device_reset(phydev, 1);
return err;
}
@@ -3801,6 +3807,9 @@ static int phy_remove(struct device *dev)
if (IS_ENABLED(CONFIG_PHYLIB_LEDS) && !phy_driver_is_genphy(phydev))
phy_leds_unregister(phydev);
+ if (!phydev->is_on_sfp_module)
+ phy_led_triggers_unregister(phydev);
+
phydev->state = PHY_DOWN;
phy_cleanup_ports(phydev);
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH 6.1.y] net: phy: register phy led_triggers during probe to avoid AB-BA deadlock
2026-03-09 10:21 FAILED: patch "[PATCH] net: phy: register phy led_triggers during probe to avoid" failed to apply to 6.1-stable tree gregkh
@ 2026-03-09 13:50 ` Sasha Levin
0 siblings, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2026-03-09 13:50 UTC (permalink / raw)
To: stable; +Cc: Andrew Lunn, Shiji Yang, Paolo Abeni, Sasha Levin
From: Andrew Lunn <andrew@lunn.ch>
[ 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 <yangshiji66@outlook.com>
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 <andrew@lunn.ch>
Tested-by: Shiji Yang <yangshiji66@outlook.com>
Link: https://patch.msgid.link/20260222152601.1978655-1-andrew@lunn.ch
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
[ dropped `is_on_sfp_module` guards and `CONFIG_PHYLIB_LEDS`/`of_phy_leds` logic ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/phy/phy_device.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index f25b0d338ca8d..11839dca8f56e 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1510,7 +1510,6 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
goto error;
phy_resume(phydev);
- phy_led_triggers_register(phydev);
return err;
@@ -1767,8 +1766,6 @@ void phy_detach(struct phy_device *phydev)
}
phydev->phylink = NULL;
- phy_led_triggers_unregister(phydev);
-
if (phydev->mdio.dev.driver)
module_put(phydev->mdio.dev.driver->owner);
@@ -3109,10 +3106,14 @@ static int phy_probe(struct device *dev)
/* Set the state to READY by default */
phydev->state = PHY_READY;
+ /* Register the PHY LED triggers */
+ phy_led_triggers_register(phydev);
+
+ return 0;
+
out:
/* Re-assert the reset signal on error */
- if (err)
- phy_device_reset(phydev, 1);
+ phy_device_reset(phydev, 1);
return err;
}
@@ -3123,6 +3124,8 @@ static int phy_remove(struct device *dev)
cancel_delayed_work_sync(&phydev->state_queue);
+ phy_led_triggers_unregister(phydev);
+
phydev->state = PHY_DOWN;
sfp_bus_del_upstream(phydev->sfp_bus);
--
2.51.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
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2026-03-09 13:50 ` [PATCH 6.1.y] net: phy: register phy led_triggers during probe to avoid AB-BA deadlock Sasha Levin
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