On Wed, Jun 24, 2020 at 11:42:59AM +0200, Jiri Slaby wrote: > On 24. 06. 20, 11:34, Greg Kroah-Hartman wrote: > > 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 <xiyuyang19@xxxxxxxxxxxx> > >> Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx> > >> --- > >> 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? > > Was this patch sent twice? As I had very same questions on the other > one, but never received a feedback: > https://lore.kernel.org/linux-serial/bf6c1e7b-3dc6-aba6-955a-fee351a6d800@xxxxxxxx/ > > > Oh, wait: this is uart_port_startup, I commented on the uart_shutdown > one. But whatever, I would scratch both of them. Yeah, you are right, dropping them both now, thanks. greg k-h
