This is a note to let you know that I've just added the patch titled
Bluetooth: hci_ldisc: Fix another race when closing the tty.
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bluetooth-hci_ldisc-fix-another-race-when-closing-the-tty.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Dec 18 13:28:59 CET 2017
From: Ronald Tschalär <ronald@xxxxxxxxxxxxx>
Date: Wed, 25 Oct 2017 22:15:19 -0700
Subject: Bluetooth: hci_ldisc: Fix another race when closing the tty.
From: Ronald Tschalär <ronald@xxxxxxxxxxxxx>
[ Upstream commit 0338b1b393ec7910898e8f7b25b3bf31a7282e16 ]
The following race condition still existed:
P1 P2
cancel_work_sync()
hci_uart_tx_wakeup()
hci_uart_write_work()
hci_uart_dequeue()
clear_bit(HCI_UART_PROTO_READY)
hci_unregister_dev(hdev)
hci_free_dev(hdev)
hu->proto->close(hu)
kfree(hu)
access to hdev and hu
Cancelling the work after clearing the HCI_UART_PROTO_READY bit avoids
this as any hci_uart_tx_wakeup() issued after the flag is cleared will
detect that and not schedule further work.
Signed-off-by: Ronald Tschalär <ronald@xxxxxxxxxxxxx>
Reviewed-by: Lukas Wunner <lukas@xxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/bluetooth/hci_ldisc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -510,13 +510,13 @@ static void hci_uart_tty_close(struct tt
if (hdev)
hci_uart_close(hdev);
- cancel_work_sync(&hu->write_work);
-
if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
write_lock_irqsave(&hu->proto_lock, flags);
clear_bit(HCI_UART_PROTO_READY, &hu->flags);
write_unlock_irqrestore(&hu->proto_lock, flags);
+ cancel_work_sync(&hu->write_work);
+
if (hdev) {
if (test_bit(HCI_UART_REGISTERED, &hu->flags))
hci_unregister_dev(hdev);
Patches currently in stable-queue which might be from ronald@xxxxxxxxxxxxx are
queue-4.14/bluetooth-hci_ldisc-fix-another-race-when-closing-the-tty.patch