Re: [PATCHv5 05/17] tty: don't allow ldisc dcd_change() after ldisc halt

Alan Cox
2010-11-24T22:56:14Z

> Yes, indeed, it's a bug. Please consider the following example:
>
> CPU1 CPU2
> =========================================================
> uart_handle_dcd_change() { tty_set_ldisc() {
> ld = tty_ldisc_ref(...) ...

[We have a reference]
> ... tty_ldisc_halt(...)
[Should block]

> I think tty code is exactly the right place to fix this bug; this is
> what my patch is for.

More special case magic on top of the current crap isn't the right fix
here, tty_ldisc_halt needs to wait for the references to hit zero.

Alan