The patch below does not apply to the 5.4-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-5.4.y git checkout FETCH_HEAD git cherry-pick -x 8466d393700f9ccef68134d3349f4e0a087679b9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025081206-rejoicing-democrat-be9e@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8466d393700f9ccef68134d3349f4e0a087679b9 Mon Sep 17 00:00:00 2001 From: Ammar Faizi ammarfaizi2@gnuweeb.org Date: Wed, 6 Aug 2025 07:31:05 +0700 Subject: [PATCH] net: usbnet: Fix the wrong netif_carrier_on() call
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 Signed-off-by: Linus Torvalds torvalds@linux-foundation.org
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 @@ -1120,6 +1120,9 @@ 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); @@ -1129,9 +1132,6 @@ static void __handle_link_change(struct usbnet *dev) * 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); }