The patch below does not apply to the 4.19-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.

thanks,

greg k-h

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

From 72ef98445aca568a81c2da050532500a8345ad3a Mon Sep 17 00:00:00 2001 From: Steven Rostedt rostedt@goodmis.org Date: Tue, 5 Apr 2022 10:02:00 -0400 Subject: [PATCH] Bluetooth: hci_qca: Use del_timer_sync() before freeing

While looking at a crash report on a timer list being corrupted, which usually happens when a timer is freed while still active. This is commonly triggered by code calling del_timer() instead of del_timer_sync() just before freeing.

One possible culprit is the hci_qca driver, which does exactly that.

Eric mentioned that wake_retrans_timer could be rearmed via the work queue, so also move the destruction of the work queue before del_timer_sync().

Cc: Eric Dumazet eric.dumazet@gmail.com Cc: stable@vger.kernel.org Fixes: 0ff252c1976da ("Bluetooth: hciuart: Add support QCA chipset for UART") Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Marcel Holtmann marcel@holtmann.org

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c index f6e91fb432a3..eab34e24d944 100644 --- a/drivers/bluetooth/hci_qca.c +++ b/drivers/bluetooth/hci_qca.c @@ -696,9 +696,9 @@ static int qca_close(struct hci_uart *hu) skb_queue_purge(&qca->tx_wait_q); skb_queue_purge(&qca->txq); skb_queue_purge(&qca->rx_memdump_q); - del_timer(&qca->tx_idle_timer); - del_timer(&qca->wake_retrans_timer); destroy_workqueue(qca->workqueue); + del_timer_sync(&qca->tx_idle_timer); + del_timer_sync(&qca->wake_retrans_timer); qca->hu = NULL;

kfree_skb(qca->rx_skb);