Messages in this thread | | | From | "Matwey V. Kornilov" <> | Date | Thu, 11 Feb 2016 23:05:45 +0300 | Subject | Re: [PATCH v1] tty: serial: 8250: Fix possible race in serial8250_em485_destroy() |
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I am sorry, please ignore it. There is no issue actually. The timer handlers and rs485_config callbacks are protected by the same spinlock, so they are never run in parallel.
2016-02-11 22:32 GMT+03:00 Matwey V. Kornilov <matwey@sai.msu.ru>: > Fix possbile race in serial8250_em485_destroy() when timer handlers can > dereference p->em485 which is alread destroyed but not yet NULLed. > > Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru> > --- > I've found that Greg applied initial patchset, so this erratum goes as separate patch. > > drivers/tty/serial/8250/8250_port.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c > index c908b77..d962de2 100644 > --- a/drivers/tty/serial/8250/8250_port.c > +++ b/drivers/tty/serial/8250/8250_port.c > @@ -617,14 +617,16 @@ EXPORT_SYMBOL_GPL(serial8250_em485_init); > */ > void serial8250_em485_destroy(struct uart_8250_port *p) > { > - if (p->em485 == NULL) > + struct uart_8250_em485 *em485 = p->em485; > + > + if (!em485) > return; > > - del_timer(&p->em485->start_tx_timer); > - del_timer(&p->em485->stop_tx_timer); > + del_timer(&em485->start_tx_timer); > + del_timer(&em485->stop_tx_timer); > > - kfree(p->em485); > p->em485 = NULL; > + kfree(em485); > } > EXPORT_SYMBOL_GPL(serial8250_em485_destroy); > > -- > 2.7.0 >
-- With best regards, Matwey V. Kornilov. Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia 119991, Moscow, Universitetsky pr-k 13, +7 (495) 9392382
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