On Wed, Jul 11, 2018 at 7:07 PM, Tycho Andersen <ty...@tycho.ws> 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? -- With Best Regards, Andy Shevchenko
