diff options
| author | Johan Hovold <johan@kernel.org> | 2020-10-25 18:45:48 +0100 |
|---|---|---|
| committer | Johan Hovold <johan@kernel.org> | 2020-11-04 11:01:08 +0100 |
| commit | 7353cad7ee4deaefc16e94727e69285563e219f6 (patch) | |
| tree | ec988e47ed724ba1961112b6efdff04c7e308e59 /drivers/usb/serial/keyspan_pda.c | |
| parent | 696c541c8c6cfa05d65aa24ae2b9e720fc01766e (diff) | |
| download | linux-7353cad7ee4deaefc16e94727e69285563e219f6.tar.gz linux-7353cad7ee4deaefc16e94727e69285563e219f6.tar.bz2 linux-7353cad7ee4deaefc16e94727e69285563e219f6.zip | |
USB: serial: keyspan_pda: fix write deadlock
The write() callback can be called in interrupt context (e.g. when used
as a console) so interrupts must be disabled while holding the port lock
to prevent a possible deadlock.
Fixes: e81ee637e4ae ("usb-serial: possible irq lock inversion (PPP vs. usb/serial)")
Fixes: 507ca9bc0476 ("[PATCH] USB: add ability for usb-serial drivers to determine if their write urb is currently being used.")
Cc: stable <stable@vger.kernel.org> # 2.6.19
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Diffstat (limited to 'drivers/usb/serial/keyspan_pda.c')
| -rw-r--r-- | drivers/usb/serial/keyspan_pda.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c index 2d5ad579475a..17b60e5a9f1f 100644 --- a/drivers/usb/serial/keyspan_pda.c +++ b/drivers/usb/serial/keyspan_pda.c @@ -443,6 +443,7 @@ static int keyspan_pda_write(struct tty_struct *tty, int request_unthrottle = 0; int rc = 0; struct keyspan_pda_private *priv; + unsigned long flags; priv = usb_get_serial_port_data(port); /* guess how much room is left in the device's ring buffer, and if we @@ -462,13 +463,13 @@ static int keyspan_pda_write(struct tty_struct *tty, the TX urb is in-flight (wait until it completes) the device is full (wait until it says there is room) */ - spin_lock_bh(&port->lock); + spin_lock_irqsave(&port->lock, flags); if (!test_bit(0, &port->write_urbs_free) || priv->tx_throttled) { - spin_unlock_bh(&port->lock); + spin_unlock_irqrestore(&port->lock, flags); return 0; } clear_bit(0, &port->write_urbs_free); - spin_unlock_bh(&port->lock); + spin_unlock_irqrestore(&port->lock, flags); /* At this point the URB is in our control, nobody else can submit it again (the only sudden transition was the one from EINPROGRESS to |