Commit 63f4c345 authored by Tony Lindgren's avatar Tony Lindgren Committed by Greg Kroah-Hartman
Browse files

serial: core: Disable uart_start() on uart_remove_one_port() 



While rebinding a uart device in a loop I noticed we may see a tx related
race on uart_remove_one_port():

uart_write from n_tty_write
n_tty_write from file_tty_write.constprop.0
file_tty_write.constprop.0 from vfs_write
vfs_write from ksys_write
ksys_write from ret_fast_syscall

Let's disallow tx on port->UPF_DEAD. This flag gets set before we start
tearing down the port in uart_remove_one_port().

Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20230419115423.59957-1-tony@atomide.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 04e82793

drivers/tty/serial/serial_core.c

+1 −1
Original line number Diff line number Diff line
@@ -135,7 +135,7 @@ static void __uart_start(struct tty_struct *tty) 
	struct uart_state *state = tty->driver_data;

	struct uart_port *port = state->uart_port;



	if (port && !uart_tx_stopped(port))

	if (port && !(port->flags & UPF_DEAD) && !uart_tx_stopped(port))

		port->ops->start_tx(port);

}