On 03/04/2015 04:39 AM, Johan Hovold wrote: > Fix overflow bug in tty_wait_until_sent on 64-bit machines, where an > infinite timeout (0) would be passed to the underlying tty-driver's > wait_until_sent-operation as a negative timeout (-1), causing it to > return immediately. Wow, that is a nasty bug. > This manifests itself for example as tcdrain() returning immediately, > drivers not honouring the drain flags when setting terminal attributes, > or even dropped data on close as a requested infinite closing-wait > timeout would be ignored. > > The first symptom was reported by Asier LLANO who noted that tcdrain() > returned prematurely when using the ftdi_sio usb-serial driver. > > Fix this by passing 0 rather than MAX_SCHEDULE_TIMEOUT (LONG_MAX) to the > underlying tty driver. > > Note that the serial-core wait_until_sent-implementation is not affected > by this bug due to a lucky chance (comparison to an unsigned maximum > timeout), and neither is the cyclades one that had an explicit check for > negative timeouts, but all other tty drivers appear to be affected. Reviewed-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
