[ +CC: Rob and Alan ]
On Thu, Jan 11, 2018 at 06:57:26PM +0100, Sebastian Andrzej Siewior wrote:
> setserial changes the IRQ via uart_set_info(). It invokes
> uart_shutdown() which free the current used IRQ and clear
> TTY_PORT_INITIALIZED. It will then update the IRQ number and invoke
> uart_startup() before returning to the caller leaving
> TTY_PORT_INITIALIZED cleared.
>
> The next open will crash with
> | list_add double add: new=ffffffff839fcc98, prev=ffffffff839fcc98, next=ffffffff839fcc98.
> since the close from the IOCTL won't free the IRQ (and clean the list)
> due to the TTY_PORT_INITIALIZED check in uart_shutdown().
>
> There is same pattern in uart_do_autoconfig() and I *think* it also
> needs to set TTY_PORT_INITIALIZED there.
> Is there a reason why uart_startup() does not set the flag by itself
> after the IRQ has been acquired (since it is cleared in uart_shutdown)?
This all seems to have been introduced by the tty-port conversion, which
left things in a slightly inconsistent state. See commits
b3b576461864 ("tty: serial_core: convert uart_open to use tty_port_open")
761ed4a94582 ("tty: serial_core: convert uart_close to use tty_port_close")
Someone else just reported what appears to be the same regression:
https://lkml.kernel.org/r/20180130220716.GA13661@xxxxxxxxxxxxxxxxx
Johan
--
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
