serial: core: Disable uart_start() on uart_remove_one_port()
authorTony Lindgren <tony@atomide.com>
Wed, 19 Apr 2023 11:54:22 +0000 (14:54 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 20 Apr 2023 11:43:44 +0000 (13:43 +0200)
commit63f4c34561718a349d321105adab028cbf212d57
tree6b53a170f76811602e726af7d5aa695dcb9abf74
parent04e82793f068d2f0ffe62fcea03d007a8cdc16a7
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: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20230419115423.59957-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serial/serial_core.c