Hi Andy, On Thu, Jul 12, 2018 at 12:03:08PM +0300, Andy Shevchenko wrote: > On Wed, Jul 11, 2018 at 7:07 PM, Tycho Andersen <tycho@xxxxxxxx> wrote: > > > Anyway, since the lock is not acquired, if uart_shutdown() is called, the > > last chunk of that function may release state->xmit.buf before its assigned > > to null, and cause the race above. > > > > To fix it, let's lock uport->lock when allocating/deallocating > > state->xmit.buf in addition to the per-port mutex. > > > * use the result of uart_port_lock() in uart_shutdown() to avoid > > uninitialized warning > > * don't use the uart_port_lock/unlock macros in uart_port_startup, > > instead test against uport directly; the compiler can't seem to "see" > > through the macros/ref/unref calls to not warn about uninitialized > > flags. We don't need to do a ref here since we hold the per-port > > mutex anyway. > > > + if (uport) > > + spin_lock_irqsave(&uport->lock, flags); > > > + if (uport) > > + spin_unlock_irqrestore(&uport->lock, flags); > > At some point it It was uart_port_lock()/uart_port_unlock(), and you > changed to simple spin lock. The macro also take reference to the > port. Do we aware about that here? I don't think so, the commit message you quoted above says, > We don't need to do a ref here since we hold the per-port mutex > anyway. Cheers, Tycho -- 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
