On Sat, Jun 13, 2020 at 08:52:18PM +0800, Xiyu Yang wrote: > uart_port_startup() invokes uart_port_lock(), which returns a reference > of the uart_port object if increases the refcount of the uart_state > object successfully or returns NULL if fails. > > However, uart_port_startup() don't take the return value of > uart_port_lock() as the new uart_port object to "uport" and use the old > "uport" instead to balance refcount in uart_port_unlock(), which may > cause a redundant decrement of refcount occurred when the new "uport" > equals to NULL and then cause a potential memory leak. > > Fix this issue by update the "uport" object to the return value of > uart_port_lock() when invoking uart_port_lock(). > > Signed-off-by: Xiyu Yang <xiyuyan...@fudan.edu.cn> > Signed-off-by: Xin Tan <tanxin....@gmail.com> > --- > drivers/tty/serial/serial_core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/serial_core.c > b/drivers/tty/serial/serial_core.c > index 57840cf90388..968fd619aec0 100644 > --- a/drivers/tty/serial/serial_core.c > +++ b/drivers/tty/serial/serial_core.c > @@ -205,7 +205,7 @@ static int uart_port_startup(struct tty_struct *tty, > struct uart_state *state, > if (!page) > return -ENOMEM; > > - uart_port_lock(state, flags); > + uport = uart_port_lock(state, flags);
How is this a different pointer than you originally had? And if it is a different pointer, shouldn't you be calling this function and using the pointer much earlier in the function instead of just here? Can you trigger a problem that this patch solves? If so, how? thanks, greg k-h
