openwrt/target/linux/generic/backport-6.6/780-16-v6.9-r8169-fix-LED-related-deadlock-on-module-removal.patch

From 19fa4f2a85d777a8052e869c1b892a2f7556569d Mon Sep 17 00:00:00 2001
From: Heiner Kallweit <hkallweit1@gmail.com>
Date: Mon, 8 Apr 2024 20:47:40 +0200
Subject: [PATCH] r8169: fix LED-related deadlock on module removal

Binding devm_led_classdev_register() to the netdev is problematic
because on module removal we get a RTNL-related deadlock. Fix this
by avoiding the device-managed LED functions.

Note: We can safely call led_classdev_unregister() for a LED even
if registering it failed, because led_classdev_unregister() detects
this and is a no-op in this case.

Fixes: 18764b883e15 ("r8169: add support for LED's on RTL8168/RTL8101")
Cc: stable@vger.kernel.org
Reported-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ethernet/realtek/r8169.h      |  6 ++--
 drivers/net/ethernet/realtek/r8169_leds.c | 35 +++++++++++++++--------
 drivers/net/ethernet/realtek/r8169_main.c |  8 ++++--
 3 files changed, 33 insertions(+), 16 deletions(-)

--- a/drivers/net/ethernet/realtek/r8169.h
+++ b/drivers/net/ethernet/realtek/r8169.h
@@ -73,6 +73,7 @@ enum mac_version {
 };
 
 struct rtl8169_private;
+struct r8169_led_classdev;
 
 void r8169_apply_firmware(struct rtl8169_private *tp);
 u16 rtl8168h_2_get_adc_bias_ioffset(struct rtl8169_private *tp);
@@ -84,7 +85,8 @@ void r8169_get_led_name(struct rtl8169_p
 			char *buf, int buf_len);
 int rtl8168_get_led_mode(struct rtl8169_private *tp);
 int rtl8168_led_mod_ctrl(struct rtl8169_private *tp, u16 mask, u16 val);
-void rtl8168_init_leds(struct net_device *ndev);
+struct r8169_led_classdev *rtl8168_init_leds(struct net_device *ndev);
 int rtl8125_get_led_mode(struct rtl8169_private *tp, int index);
 int rtl8125_set_led_mode(struct rtl8169_private *tp, int index, u16 mode);
-void rtl8125_init_leds(struct net_device *ndev);
+struct r8169_led_classdev *rtl8125_init_leds(struct net_device *ndev);
+void r8169_remove_leds(struct r8169_led_classdev *leds);
--- a/drivers/net/ethernet/realtek/r8169_leds.c
+++ b/drivers/net/ethernet/realtek/r8169_leds.c
@@ -147,22 +147,22 @@ static void rtl8168_setup_ldev(struct r8
 	led_cdev->hw_control_get_device = r8169_led_hw_control_get_device;
 
 	/* ignore errors */
-	devm_led_classdev_register(&ndev->dev, led_cdev);
+	led_classdev_register(&ndev->dev, led_cdev);
 }
 
-void rtl8168_init_leds(struct net_device *ndev)
+struct r8169_led_classdev *rtl8168_init_leds(struct net_device *ndev)
 {
-	/* bind resource mgmt to netdev */
-	struct device *dev = &ndev->dev;
 	struct r8169_led_classdev *leds;
 	int i;
 
-	leds = devm_kcalloc(dev, RTL8168_NUM_LEDS, sizeof(*leds), GFP_KERNEL);
+	leds = kcalloc(RTL8168_NUM_LEDS + 1, sizeof(*leds), GFP_KERNEL);
 	if (!leds)
-		return;
+		return NULL;
 
 	for (i = 0; i < RTL8168_NUM_LEDS; i++)
 		rtl8168_setup_ldev(leds + i, ndev, i);
+
+	return leds;
 }
 
 static int rtl8125_led_hw_control_is_supported(struct led_classdev *led_cdev,
@@ -246,20 +246,31 @@ static void rtl8125_setup_led_ldev(struc
 	led_cdev->hw_control_get_device = r8169_led_hw_control_get_device;
 
 	/* ignore errors */
-	devm_led_classdev_register(&ndev->dev, led_cdev);
+	led_classdev_register(&ndev->dev, led_cdev);
 }
 
-void rtl8125_init_leds(struct net_device *ndev)
+struct r8169_led_classdev *rtl8125_init_leds(struct net_device *ndev)
 {
-	/* bind resource mgmt to netdev */
-	struct device *dev = &ndev->dev;
 	struct r8169_led_classdev *leds;
 	int i;
 
-	leds = devm_kcalloc(dev, RTL8125_NUM_LEDS, sizeof(*leds), GFP_KERNEL);
+	leds = kcalloc(RTL8125_NUM_LEDS + 1, sizeof(*leds), GFP_KERNEL);
 	if (!leds)
-		return;
+		return NULL;
 
 	for (i = 0; i < RTL8125_NUM_LEDS; i++)
 		rtl8125_setup_led_ldev(leds + i, ndev, i);
+
+	return leds;
+}
+
+void r8169_remove_leds(struct r8169_led_classdev *leds)
+{
+	if (!leds)
+		return;
+
+	for (struct r8169_led_classdev *l = leds; l->ndev; l++)
+		led_classdev_unregister(&l->led);
+
+	kfree(leds);
 }
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -674,6 +674,8 @@ struct rtl8169_private {
 	const char *fw_name;
 	struct rtl_fw *rtl_fw;
 
+	struct r8169_led_classdev *leds;
+
 	u32 ocp_base;
 };
 
@@ -5067,6 +5069,8 @@ static void rtl_remove_one(struct pci_de
 
 	cancel_work_sync(&tp->wk.work);
 
+	r8169_remove_leds(tp->leds);
+
 	unregister_netdev(tp->dev);
 
 	if (tp->dash_type != RTL_DASH_NONE)
@@ -5525,9 +5529,9 @@ static int rtl_init_one(struct pci_dev *
 
 	if (IS_ENABLED(CONFIG_R8169_LEDS)) {
 		if (rtl_is_8125(tp))
-			rtl8125_init_leds(dev);
+			tp->leds = rtl8125_init_leds(dev);
 		else if (tp->mac_version > RTL_GIGA_MAC_VER_06)
-			rtl8168_init_leds(dev);
+			tp->leds = rtl8168_init_leds(dev);
 	}
 
 	netdev_info(dev, "%s, %pM, XID %03x, IRQ %d\n",