FAILED: patch "[PATCH] Bluetooth: hci_uart: clear HCI_UART_SENDING when write_work" failed to apply to 5.10-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.10-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-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 1b0d946d6f08bd39211385bc703a440911b41e46
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071338-expend-curing-7388@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1b0d946d6f08bd39211385bc703a440911b41e46 Mon Sep 17 00:00:00 2001
From: Pauli Virtanen <pav@iki.fi>
Date: Sat, 13 Jun 2026 21:43:37 +0300
Subject: [PATCH] Bluetooth: hci_uart: clear HCI_UART_SENDING when write_work
 is canceled

HCI_UART_SENDING bit in tx_state means write_work is pending and blocks
queueing it again.  Currently this bit is not cleared when canceling the
work in hci_uart_close(), which blocks future writes when device is
reopened later if write_work was pending.

Fix by clearing HCI_UART_SENDING when canceling the work.

Also make clearing of tx_skb safe by using disable_work_sync +
enable_work instead of just cancel_work_sync.  hci_uart_flush() purges
the proto tx queue so we can cancel the pending write_work there,
instead of doing it just in hci_uart_close().  Re-enable and possibly
requeue the work after queue flush.

Fixes: c1bb9336ae6b ("Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths")
Link: https://lore.kernel.org/linux-bluetooth/07e0a28650773abec711ee492fdb1bf5d21a6c98.camel@iki.fi/
Cc: stable@vger.kernel.org
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index 47f4902b40b4..2ad42c3bbaac 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -239,6 +239,8 @@ static int hci_uart_flush(struct hci_dev *hdev)
 
 	BT_DBG("hdev %p tty %p", hdev, tty);
 
+	disable_work_sync(&hu->write_work);
+
 	if (hu->tx_skb) {
 		kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
 	}
@@ -254,6 +256,14 @@ static int hci_uart_flush(struct hci_dev *hdev)
 
 	percpu_up_read(&hu->proto_lock);
 
+	/* Resume TX. Also reschedule in case work was queued concurrently;
+	 * this may schedule write_work although there's nothing to do.
+	 */
+	enable_work(&hu->write_work);
+	clear_bit(HCI_UART_SENDING, &hu->tx_state);
+	if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
+		hci_uart_tx_wakeup(hu);
+
 	return 0;
 }
 
@@ -271,12 +281,8 @@ static int hci_uart_open(struct hci_dev *hdev)
 /* Close device */
 static int hci_uart_close(struct hci_dev *hdev)
 {
-	struct hci_uart *hu = hci_get_drvdata(hdev);
-
 	BT_DBG("hdev %p", hdev);
 
-	cancel_work_sync(&hu->write_work);
-
 	hci_uart_flush(hdev);
 	hdev->flush = NULL;
 	return 0;