The commit referenced in the Fixes tag causes usbnet to malfunction (identified via git bisect). Post-commit, my external RJ45 LAN cable fails to connect. Linus also reported the same issue after pulling that commit.

The code has a logic error: netif_carrier_on() is only called when the link is already on. Fix this by moving the netif_carrier_on() call outside the if-statement entirely. This ensures it is always called when EVENT_LINK_CARRIER_ON is set and properly clears it regardless of the link state.

Cc: stable@vger.kernel.org Cc: Armando Budianto sprite@gnuweeb.org Reviewed-by: Simon Horman horms@kernel.org Suggested-by: Linus Torvalds torvalds@linux-foundation.org Link: https://lore.kernel.org/all/CAHk-=wjqL4uF0MG_c8+xHX1Vv8==sPYQrtzbdA3kzi96284... Closes: https://lore.kernel.org/netdev/CAHk-=wjKh8X4PT_mU1kD4GQrbjivMfPn-_hXa6han_BT... Closes: https://lore.kernel.org/netdev/0752dee6-43d6-4e1f-81d2-4248142cccd2@gnuweeb.... Fixes: 0d9cfc9b8cb1 ("net: usbnet: Avoid potential RCU stall on LINK_CHANGE event") Signed-off-by: Ammar Faizi ammarfaizi2@gnuweeb.org ---

v3: - Move the netif_carrier_on() call outside of the if-statement entirely (Linus).

v2: - Rebase on top of the latest netdev/net tree. The previous patch was based on 0d9cfc9b8cb1. Line numbers have changed since then. Link: https://lore.gnuweeb.org/gwml/20250801190310.58443-1-ammarfaizi2@gnuweeb.org

drivers/net/usb/usbnet.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index a38ffbf4b3f0..511c4154cf74 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -1113,32 +1113,32 @@ static const struct ethtool_ops usbnet_ethtool_ops = { .set_link_ksettings = usbnet_set_link_ksettings_mii, };

/*-------------------------------------------------------------------------*/

static void __handle_link_change(struct usbnet *dev) { if (!test_bit(EVENT_DEV_OPEN, &dev->flags)) return;

+ if (test_and_clear_bit(EVENT_LINK_CARRIER_ON, &dev->flags)) + netif_carrier_on(dev->net); + if (!netif_carrier_ok(dev->net)) { /* kill URBs for reading packets to save bus bandwidth */ unlink_urbs(dev, &dev->rxq);

/* * tx_timeout will unlink URBs for sending packets and * tx queue is stopped by netcore after link becomes off */ } else { - if (test_and_clear_bit(EVENT_LINK_CARRIER_ON, &dev->flags)) - netif_carrier_on(dev->net); - /* submitting URBs for reading packets */ queue_work(system_bh_wq, &dev->bh_work); }

/* hard_mtu or rx_urb_size may change during link change */ usbnet_update_max_qlen(dev);

clear_bit(EVENT_LINK_CHANGE, &dev->flags); }