kernel/drivers/net/usb/lan78xx.c, branch linux-rolling-stable

net: usb: lan78xx: skip LTM configuration for LAN7850

2026-03-19T15:15:00Z

commit d9cc0e440f0664f6f3e2c26e39ab9dd5f3badba7 upstream. Do not configure Latency Tolerance Messaging (LTM) on USB 2.0 hardware. The LAN7850 is a High-Speed (USB 2.0) only device and does not support SuperSpeed features like LTM. Currently, the driver unconditionally attempts to configure LTM registers during initialization. On the LAN7850, these registers do not exist, resulting in writes to invalid or undocumented memory space. This issue was identified during a port to the regmap API with strict register validation enabled. While no functional issues or crashes have been observed from these invalid writes, bypassing LTM initialization on the LAN7850 ensures the driver strictly adheres to the hardware's valid register map. Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver") Cc: stable@vger.kernel.org Signed-off-by: Oleksij Rempel Link: https://patch.msgid.link/20260305143429.530909-4-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net: usb: lan78xx: fix WARN in __netif_napi_del_locked on disconnect

2026-03-19T15:15:00Z

commit 312c816c6bc30342bc30dca0d6db617ab4d3ae4e upstream. Remove redundant netif_napi_del() call from disconnect path. A WARN may be triggered in __netif_napi_del_locked() during USB device disconnect: WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350 This happens because netif_napi_del() is called in the disconnect path while NAPI is still enabled. However, it is not necessary to call netif_napi_del() explicitly, since unregister_netdev() will handle NAPI teardown automatically and safely. Removing the redundant call avoids triggering the warning. Full trace: lan78xx 1-1:1.0 enu1: Failed to read register index 0x000000c4. ret = -ENODEV lan78xx 1-1:1.0 enu1: Failed to set MAC down with error -ENODEV lan78xx 1-1:1.0 enu1: Link is Down lan78xx 1-1:1.0 enu1: Failed to read register index 0x00000120. ret = -ENODEV ------------[ cut here ]------------ WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350 Modules linked in: flexcan can_dev fuse CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 6.16.0-rc2-00624-ge926949dab03 #9 PREEMPT Hardware name: SKOV IMX8MP CPU revC - bd500 (DT) Workqueue: usb_hub_wq hub_event pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __netif_napi_del_locked+0x2b4/0x350 lr : __netif_napi_del_locked+0x7c/0x350 sp : ffffffc085b673c0 x29: ffffffc085b673c0 x28: ffffff800b7f2000 x27: ffffff800b7f20d8 x26: ffffff80110bcf58 x25: ffffff80110bd978 x24: 1ffffff0022179eb x23: ffffff80110bc000 x22: ffffff800b7f5000 x21: ffffff80110bc000 x20: ffffff80110bcf38 x19: ffffff80110bcf28 x18: dfffffc000000000 x17: ffffffc081578940 x16: ffffffc08284cee0 x15: 0000000000000028 x14: 0000000000000006 x13: 0000000000040000 x12: ffffffb0022179e8 x11: 1ffffff0022179e7 x10: ffffffb0022179e7 x9 : dfffffc000000000 x8 : 0000004ffdde8619 x7 : ffffff80110bcf3f x6 : 0000000000000001 x5 : ffffff80110bcf38 x4 : ffffff80110bcf38 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 1ffffff0022179e7 x0 : 0000000000000000 Call trace: __netif_napi_del_locked+0x2b4/0x350 (P) lan78xx_disconnect+0xf4/0x360 usb_unbind_interface+0x158/0x718 device_remove+0x100/0x150 device_release_driver_internal+0x308/0x478 device_release_driver+0x1c/0x30 bus_remove_device+0x1a8/0x368 device_del+0x2e0/0x7b0 usb_disable_device+0x244/0x540 usb_disconnect+0x220/0x758 hub_event+0x105c/0x35e0 process_one_work+0x760/0x17b0 worker_thread+0x768/0xce8 kthread+0x3bc/0x690 ret_from_fork+0x10/0x20 irq event stamp: 211604 hardirqs last enabled at (211603): [] _raw_spin_unlock_irqrestore+0x84/0x98 hardirqs last disabled at (211604): [] el1_dbg+0x24/0x80 softirqs last enabled at (211296): [] handle_softirqs+0x820/0xbc8 softirqs last disabled at (210993): [] __do_softirq+0x18/0x20 ---[ end trace 0000000000000000 ]--- lan78xx 1-1:1.0 enu1: failed to kill vid 0081/0 Fixes: e110bc825897 ("net: usb: lan78xx: Convert to PHYLINK for improved PHY and MAC management") Cc: stable@vger.kernel.org Signed-off-by: Oleksij Rempel Link: https://patch.msgid.link/20260305143429.530909-5-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net: usb: lan78xx: fix TX byte statistics for small packets

2026-03-19T15:15:00Z

commit 50988747c30df47b73b787f234f746027cb7ec6c upstream. Account for hardware auto-padding in TX byte counters to reflect actual wire traffic. The LAN7850 hardware automatically pads undersized frames to the minimum Ethernet frame length (ETH_ZLEN, 60 bytes). However, the driver tracks the network statistics based on the unpadded socket buffer length. This results in the tx_bytes counter under-reporting the actual physical bytes placed on the Ethernet wire for small packets (like short ARP or ICMP requests). Use max_t() to ensure the transmission statistics accurately account for the hardware-generated padding. Fixes: d383216a7efe ("lan78xx: Introduce Tx URB processing improvements") Cc: stable@vger.kernel.org Signed-off-by: Oleksij Rempel Link: https://patch.msgid.link/20260305143429.530909-3-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net: usb: lan78xx: fix silent drop of packets with checksum errors

2026-03-19T15:15:00Z

commit e4f774a0cc955ce762aec91c66915a6e15087ab7 upstream. Do not drop packets with checksum errors at the USB driver level; pass them to the network stack. Previously, the driver dropped all packets where the 'Receive Error Detected' (RED) bit was set, regardless of the specific error type. This caused packets with only IP or TCP/UDP checksum errors to be dropped before reaching the kernel, preventing the network stack from accounting for them or performing software fallback. Add a mask for hard hardware errors to safely drop genuinely corrupt frames, while allowing checksum-errored frames to pass with their ip_summed field explicitly set to CHECKSUM_NONE. Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver") Cc: stable@vger.kernel.org Signed-off-by: Oleksij Rempel Link: https://patch.msgid.link/20260305143429.530909-2-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net: usb: lan78xx: scan all MDIO addresses on LAN7801

2026-03-04T12:20:52Z

[ Upstream commit f1e2f0ce704e4a14e3f367d3b97d3dd2d8e183b7 ] The LAN7801 is designed exclusively for external PHYs (unlike the LAN7800/LAN7850 which have internal PHYs), but lan78xx_mdio_init() restricts PHY scanning to MDIO addresses 0-7 by setting phy_mask to ~(0xFF). This prevents discovery of external PHYs wired to addresses outside that range. One such case is the DP83TC814 100BASE-T1 PHY, which is typically configured at MDIO address 10 via PHYAD bootstrap pins and goes undetected with the current mask. Remove the restrictive phy_mask assignment for the LAN7801 so that the default mask of 0 applies, allowing all 32 MDIO addresses to be scanned during bus registration. Fixes: 02dc1f3d613d ("lan78xx: add LAN7801 MAC only support") Signed-off-by: Martin Pålsson Link: https://patch.msgid.link/0110019c6f388aff-98d99cf0-4425-4fff-b16b-dea5ad8fafe0-000000@eu-north-1.amazonses.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: usb: lan78xx: fix use of improperly initialized dev->chipid in lan78xx_reset

2025-10-16T01:27:48Z

dev->chipid is used in lan78xx_init_mac_address before it's initialized: lan78xx_reset() { lan78xx_init_mac_address() lan78xx_read_eeprom() lan78xx_read_raw_eeprom() <- dev->chipid is used here dev->chipid = ... <- dev->chipid is initialized correctly here } Reorder initialization so that dev->chipid is set before calling lan78xx_init_mac_address(). Fixes: a0db7d10b76e ("lan78xx: Add to handle mux control per chip id") Signed-off-by: I Viswanath Reviewed-by: Vadim Fedorenko Reviewed-by: Khalid Aziz Link: https://patch.msgid.link/20251013181648.35153-1-viswanathiyyappan@gmail.com Signed-off-by: Jakub Kicinski

net: usb: lan78xx: Fix lost EEPROM write timeout error(-ETIMEDOUT) in lan78xx_write_raw_eeprom

2025-10-12T17:13:39Z

The function lan78xx_write_raw_eeprom failed to properly propagate EEPROM write timeout errors (-ETIMEDOUT). In the timeout fallthrough path, it first attempted to restore the pin configuration for LED outputs and then returned only the status of that restore operation, discarding the original timeout error saved in ret. As a result, callers could mistakenly treat EEPROM write operation as successful even though the EEPROM write had actually timed out with no or partial data write. To fix this, handle errors in restoring the LED pin configuration separately. If the restore succeeds, return any prior EEPROM write timeout error saved in ret to the caller. Suggested-by: Oleksij Rempel Fixes: 8b1b2ca83b20 ("net: usb: lan78xx: Improve error handling in EEPROM and OTP operations") cc: stable@vger.kernel.org Signed-off-by: Bhanu Seshu Kumar Valluri Reviewed-by: Simon Horman Signed-off-by: David S. Miller

net: usb: lan78xx: Fix lost EEPROM read timeout error(-ETIMEDOUT) in lan78xx_read_raw_eeprom

2025-10-03T17:15:35Z

Syzbot reported read of uninitialized variable BUG with following call stack. lan78xx 8-1:1.0 (unnamed net_device) (uninitialized): EEPROM read operation timeout ===================================================== BUG: KMSAN: uninit-value in lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1095 [inline] BUG: KMSAN: uninit-value in lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline] BUG: KMSAN: uninit-value in lan78xx_reset+0x999/0x2cd0 drivers/net/usb/lan78xx.c:3241 lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1095 [inline] lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline] lan78xx_reset+0x999/0x2cd0 drivers/net/usb/lan78xx.c:3241 lan78xx_bind+0x711/0x1690 drivers/net/usb/lan78xx.c:3766 lan78xx_probe+0x225c/0x3310 drivers/net/usb/lan78xx.c:4707 Local variable sig.i.i created at: lan78xx_read_eeprom drivers/net/usb/lan78xx.c:1092 [inline] lan78xx_init_mac_address drivers/net/usb/lan78xx.c:1937 [inline] lan78xx_reset+0x77e/0x2cd0 drivers/net/usb/lan78xx.c:3241 lan78xx_bind+0x711/0x1690 drivers/net/usb/lan78xx.c:3766 The function lan78xx_read_raw_eeprom failed to properly propagate EEPROM read timeout errors (-ETIMEDOUT). In the fallthrough path, it first attempted to restore the pin configuration for LED outputs and then returned only the status of that restore operation, discarding the original timeout error. As a result, callers could mistakenly treat the data buffer as valid even though the EEPROM read had actually timed out with no data or partial data. To fix this, handle errors in restoring the LED pin configuration separately. If the restore succeeds, return any prior EEPROM timeout error correctly to the caller. Reported-by: syzbot+62ec8226f01cb4ca19d9@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=62ec8226f01cb4ca19d9 Fixes: 8b1b2ca83b20 ("net: usb: lan78xx: Improve error handling in EEPROM and OTP operations") Signed-off-by: Bhanu Seshu Kumar Valluri Reviewed-by: Oleksij Rempel Link: https://patch.msgid.link/20250930084902.19062-1-bhanuseshukumar@gmail.com Signed-off-by: Jakub Kicinski

net: usb: lan78xx: add support for generic net selftests via ethtool

2025-08-25T23:22:19Z

Integrate generic net_selftest framework by wiring up .get_strings, .get_sset_count, and .self_test ethtool ops. This enables execution of standard self-tests using `ethtool -t ` on LAN78xx devices. Signed-off-by: Oleksij Rempel Link: https://patch.msgid.link/20250822092555.2888870-1-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski

net: usb: lan78xx: stop including phy_fixed.h

2025-07-07T21:30:09Z

Since e110bc825897 ("net: usb: lan78xx: Convert to PHYLINK for improved PHY and MAC management") this header isn't needed any longer. Signed-off-by: Heiner Kallweit Reviewed-by: Andrew Lunn Link: https://patch.msgid.link/626d389a-0f33-4b45-8949-ad53e89c36f5@gmail.com Signed-off-by: Jakub Kicinski