Messages in this thread | | | Date | Wed, 6 Apr 2022 08:39:07 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH] Bluetooth: hci_qca: Use del_timer_sync() before freeing |
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On Mon, Apr 04, 2022 at 05:22:00PM -0700, Eric Dumazet wrote: > > On 4/4/22 15:22, Steven Rostedt wrote: > > [ Resending due to cut and paste failure of email address ] > > > > From: Steven Rostedt (Google) <rostedt@goodmis.org> > > > > 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. > > > > Cc: stable@vger.kernel.org > > Fixes: 0ff252c1976da ("Bluetooth: hciuart: Add support QCA chipset for > > UART") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> > > --- > > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c > > index f6e91fb432a3..73a8c72b5aae 100644 > > --- a/drivers/bluetooth/hci_qca.c > > +++ b/drivers/bluetooth/hci_qca.c > > @@ -696,8 +696,8 @@ 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); > > + del_timer_sync(&qca->tx_idle_timer); > > + del_timer_sync(&qca->wake_retrans_timer); > > > It seems the wake_retrans_timer could be re-armed from a work queue. > > So perhaps we need to make sure qca->workqueue is destroyed > > before these del_timer_sync() calls ? > > > destroy_workqueue(qca->workqueue); > > > ie move this destroy_workqueue() up ? >
What prevents the timer code from queueing work into the destroyed workqueue ?
Thanks, Guenter
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