[SRU] [Noble] [PATCH 1/1] net: usb: usbnet: restore usb%d name exception for local mac addresses

[SRU] [Noble] [PATCH 1/1] net: usb: usbnet: restore usb%d name exception for local mac addresses

[Jianlin Lv]

From: Dominique Martinet <dominique.martinet@atmark-techno.com>

commit 8a7d12d674ac ("net: usb: usbnet: fix name regression") assumed
that local addresses always came from the kernel, but some devices hand
out local mac addresses so we ended up with point-to-point devices with
a mac set by the driver, renaming to eth%d when they used to be named
usb%d.

Userspace should not rely on device name, but for the sake of stability
restore the local mac address check portion of the naming exception:
point to point devices which either have no mac set by the driver or
have a local mac handed out by the driver will keep the usb%d name.

(some USB LTE modems are known to hand out a stable mac from the locally
administered range; that mac appears to be random (different for
mulitple devices) and can be reset with device-specific commands, so
while such devices would benefit from getting a OUI reserved, we have
to deal with these and might as well preserve the existing behavior
to avoid breaking fragile openwrt configurations and such on upgrade.)

Link: https://lkml.kernel.org/r/20241203130457.904325-1-asmadeus@codewreck.org
Fixes: 8a7d12d674ac ("net: usb: usbnet: fix name regression")
Cc: stable@vger.kernel.org
Tested-by: Ahmed Naseef <naseefkm@gmail.com>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Acked-by: Oliver Neukum <oneukum@suse.com>
Link: https://patch.msgid.link/20250326-usbnet_rename-v2-1-57eb21fcff26@atmark-techno.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

(cherry picked from commit 2ea396448f26d0d7d66224cb56500a6789c7ed07)
Signed-off-by: Jianlin Lv <iecedge@gmail.com>
---
 drivers/net/usb/usbnet.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 9f66c47dc58b..08cbc8e4b361 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -178,6 +178,17 @@ int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
 }
 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
 
+static bool usbnet_needs_usb_name_format(struct usbnet *dev, struct net_device *net)
+{
+	/* Point to point devices which don't have a real MAC address
+	 * (or report a fake local one) have historically used the usb%d
+	 * naming. Preserve this..
+	 */
+	return (dev->driver_info->flags & FLAG_POINTTOPOINT) != 0 &&
+		(is_zero_ether_addr(net->dev_addr) ||
+		 is_local_ether_addr(net->dev_addr));
+}
+
 static void intr_complete (struct urb *urb)
 {
 	struct usbnet	*dev = urb->context;
@@ -1766,13 +1777,11 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
 		if (status < 0)
 			goto out1;
 
-		// heuristic:  "usb%d" for links we know are two-host,
-		// else "eth%d" when there's reasonable doubt.  userspace
-		// can rename the link if it knows better.
+		/* heuristic: rename to "eth%d" if we are not sure this link
+		 * is two-host (these links keep "usb%d")
+		 */
 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
-		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
-		     /* somebody touched it*/
-		     !is_zero_ether_addr(net->dev_addr)))
+		    !usbnet_needs_usb_name_format(dev, net))
 			strscpy(net->name, "eth%d", sizeof(net->name));
 		/* WLAN devices should always be named "wlan%d" */
 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
-- 
2.34.1

[SRU] [Noble] [PATCH 1/1] net: usb: usbnet: restore usb%d name exception for local mac addresses

[Jianlin Lv]

From: Dominique Martinet <dominique.martinet@atmark-techno.com>

commit 8a7d12d674ac ("net: usb: usbnet: fix name regression") assumed
that local addresses always came from the kernel, but some devices hand
out local mac addresses so we ended up with point-to-point devices with
a mac set by the driver, renaming to eth%d when they used to be named
usb%d.

Userspace should not rely on device name, but for the sake of stability
restore the local mac address check portion of the naming exception:
point to point devices which either have no mac set by the driver or
have a local mac handed out by the driver will keep the usb%d name.

(some USB LTE modems are known to hand out a stable mac from the locally
administered range; that mac appears to be random (different for
mulitple devices) and can be reset with device-specific commands, so
while such devices would benefit from getting a OUI reserved, we have
to deal with these and might as well preserve the existing behavior
to avoid breaking fragile openwrt configurations and such on upgrade.)

Link: https://lkml.kernel.org/r/20241203130457.904325-1-asmadeus@codewreck.org
Fixes: 8a7d12d674ac ("net: usb: usbnet: fix name regression")
Cc: stable@vger.kernel.org
Tested-by: Ahmed Naseef <naseefkm@gmail.com>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Acked-by: Oliver Neukum <oneukum@suse.com>
Link: https://patch.msgid.link/20250326-usbnet_rename-v2-1-57eb21fcff26@atmark-techno.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

(cherry picked from commit 2ea396448f26d0d7d66224cb56500a6789c7ed07)
Signed-off-by: Jianlin Lv <iecedge@gmail.com>
---
 drivers/net/usb/usbnet.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 9f66c47dc58b..08cbc8e4b361 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -178,6 +178,17 @@ int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
 }
 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
 
+static bool usbnet_needs_usb_name_format(struct usbnet *dev, struct net_device *net)
+{
+	/* Point to point devices which don't have a real MAC address
+	 * (or report a fake local one) have historically used the usb%d
+	 * naming. Preserve this..
+	 */
+	return (dev->driver_info->flags & FLAG_POINTTOPOINT) != 0 &&
+		(is_zero_ether_addr(net->dev_addr) ||
+		 is_local_ether_addr(net->dev_addr));
+}
+
 static void intr_complete (struct urb *urb)
 {
 	struct usbnet	*dev = urb->context;
@@ -1766,13 +1777,11 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
 		if (status < 0)
 			goto out1;
 
-		// heuristic:  "usb%d" for links we know are two-host,
-		// else "eth%d" when there's reasonable doubt.  userspace
-		// can rename the link if it knows better.
+		/* heuristic: rename to "eth%d" if we are not sure this link
+		 * is two-host (these links keep "usb%d")
+		 */
 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
-		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
-		     /* somebody touched it*/
-		     !is_zero_ether_addr(net->dev_addr)))
+		    !usbnet_needs_usb_name_format(dev, net))
 			strscpy(net->name, "eth%d", sizeof(net->name));
 		/* WLAN devices should always be named "wlan%d" */
 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
-- 
2.34.1

[SRU] [Noble] [PATCH 1/1] net: usb: usbnet: restore usb%d name exception for local mac addresses

[Jianlin Lv]

From: Dominique Martinet <dominique.martinet@atmark-techno.com>

BugLink: https://bugs.launchpad.net/bugs/2111592

commit 8a7d12d674ac ("net: usb: usbnet: fix name regression") assumed
that local addresses always came from the kernel, but some devices hand
out local mac addresses so we ended up with point-to-point devices with
a mac set by the driver, renaming to eth%d when they used to be named
usb%d.

Userspace should not rely on device name, but for the sake of stability
restore the local mac address check portion of the naming exception:
point to point devices which either have no mac set by the driver or
have a local mac handed out by the driver will keep the usb%d name.

(some USB LTE modems are known to hand out a stable mac from the locally
administered range; that mac appears to be random (different for
mulitple devices) and can be reset with device-specific commands, so
while such devices would benefit from getting a OUI reserved, we have
to deal with these and might as well preserve the existing behavior
to avoid breaking fragile openwrt configurations and such on upgrade.)

Link: https://lkml.kernel.org/r/20241203130457.904325-1-asmadeus@codewreck.org
Fixes: 8a7d12d674ac ("net: usb: usbnet: fix name regression")
Cc: stable@vger.kernel.org
Tested-by: Ahmed Naseef <naseefkm@gmail.com>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Acked-by: Oliver Neukum <oneukum@suse.com>
Link: https://patch.msgid.link/20250326-usbnet_rename-v2-1-57eb21fcff26@atmark-techno.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

(cherry picked from commit 2ea396448f26d0d7d66224cb56500a6789c7ed07)
Signed-off-by: Jianlin Lv <iecedge@gmail.com>
---
 drivers/net/usb/usbnet.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 9f66c47dc58b..08cbc8e4b361 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -178,6 +178,17 @@ int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
 }
 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
 
+static bool usbnet_needs_usb_name_format(struct usbnet *dev, struct net_device *net)
+{
+	/* Point to point devices which don't have a real MAC address
+	 * (or report a fake local one) have historically used the usb%d
+	 * naming. Preserve this..
+	 */
+	return (dev->driver_info->flags & FLAG_POINTTOPOINT) != 0 &&
+		(is_zero_ether_addr(net->dev_addr) ||
+		 is_local_ether_addr(net->dev_addr));
+}
+
 static void intr_complete (struct urb *urb)
 {
 	struct usbnet	*dev = urb->context;
@@ -1766,13 +1777,11 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
 		if (status < 0)
 			goto out1;
 
-		// heuristic:  "usb%d" for links we know are two-host,
-		// else "eth%d" when there's reasonable doubt.  userspace
-		// can rename the link if it knows better.
+		/* heuristic: rename to "eth%d" if we are not sure this link
+		 * is two-host (these links keep "usb%d")
+		 */
 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
-		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
-		     /* somebody touched it*/
-		     !is_zero_ether_addr(net->dev_addr)))
+		    !usbnet_needs_usb_name_format(dev, net))
 			strscpy(net->name, "eth%d", sizeof(net->name));
 		/* WLAN devices should always be named "wlan%d" */
 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
-- 
2.34.1

Re: [SRU] [Noble] [PATCH 1/1] net: usb: usbnet: restore usb%d name exception for local mac addresses

[Greg KH]

On Fri, May 23, 2025 at 05:37:23PM +0800, Jianlin Lv wrote:
> From: Dominique Martinet <dominique.martinet@atmark-techno.com>
> 
> commit 8a7d12d674ac ("net: usb: usbnet: fix name regression") assumed
> that local addresses always came from the kernel, but some devices hand
> out local mac addresses so we ended up with point-to-point devices with
> a mac set by the driver, renaming to eth%d when they used to be named
> usb%d.
> 
> Userspace should not rely on device name, but for the sake of stability
> restore the local mac address check portion of the naming exception:
> point to point devices which either have no mac set by the driver or
> have a local mac handed out by the driver will keep the usb%d name.
> 
> (some USB LTE modems are known to hand out a stable mac from the locally
> administered range; that mac appears to be random (different for
> mulitple devices) and can be reset with device-specific commands, so
> while such devices would benefit from getting a OUI reserved, we have
> to deal with these and might as well preserve the existing behavior
> to avoid breaking fragile openwrt configurations and such on upgrade.)
> 
> Link: https://lkml.kernel.org/r/20241203130457.904325-1-asmadeus@codewreck.org
> Fixes: 8a7d12d674ac ("net: usb: usbnet: fix name regression")
> Cc: stable@vger.kernel.org
> Tested-by: Ahmed Naseef <naseefkm@gmail.com>
> Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
> Acked-by: Oliver Neukum <oneukum@suse.com>
> Link: https://patch.msgid.link/20250326-usbnet_rename-v2-1-57eb21fcff26@atmark-techno.com
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> 
> (cherry picked from commit 2ea396448f26d0d7d66224cb56500a6789c7ed07)
> Signed-off-by: Jianlin Lv <iecedge@gmail.com>
> ---

What stable branch is this backport for?

confused,

greg k-h

Re: [SRU] [Noble] [PATCH 1/1] net: usb: usbnet: restore usb%d name exception for local mac addresses

[Greg KH]

On Fri, May 23, 2025 at 10:30:58PM +0800, Jianlin Lv wrote:
> From: Dominique Martinet <dominique.martinet@atmark-techno.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/2111592
> 
> commit 8a7d12d674ac ("net: usb: usbnet: fix name regression") assumed
> that local addresses always came from the kernel, but some devices hand
> out local mac addresses so we ended up with point-to-point devices with
> a mac set by the driver, renaming to eth%d when they used to be named
> usb%d.
> 
> Userspace should not rely on device name, but for the sake of stability
> restore the local mac address check portion of the naming exception:
> point to point devices which either have no mac set by the driver or
> have a local mac handed out by the driver will keep the usb%d name.
> 
> (some USB LTE modems are known to hand out a stable mac from the locally
> administered range; that mac appears to be random (different for
> mulitple devices) and can be reset with device-specific commands, so
> while such devices would benefit from getting a OUI reserved, we have
> to deal with these and might as well preserve the existing behavior
> to avoid breaking fragile openwrt configurations and such on upgrade.)
> 
> Link: https://lkml.kernel.org/r/20241203130457.904325-1-asmadeus@codewreck.org
> Fixes: 8a7d12d674ac ("net: usb: usbnet: fix name regression")
> Cc: stable@vger.kernel.org
> Tested-by: Ahmed Naseef <naseefkm@gmail.com>
> Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
> Acked-by: Oliver Neukum <oneukum@suse.com>
> Link: https://patch.msgid.link/20250326-usbnet_rename-v2-1-57eb21fcff26@atmark-techno.com
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> 
> (cherry picked from commit 2ea396448f26d0d7d66224cb56500a6789c7ed07)
> Signed-off-by: Jianlin Lv <iecedge@gmail.com>
> ---
>  drivers/net/usb/usbnet.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)

This is already in all stable kernel branches, why send it again?

confused,

greg k-h