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Commit eea7e17e authored by Linus Torvalds's avatar Linus Torvalds
Browse files

tty, serial: Fix race and NULL check in uart_close() 



Commit 46d57a44 ("serial: use tty_port pointers in the core code")
contained two bugs that causes (rare) crashes:

 - the rename typoed one site

 - a NULL check was missed

Reported-and-tested-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: Greg KH <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d93a8f82

drivers/serial/serial_core.c

+5 −2
Original line number Diff line number Diff line
@@ -1270,6 +1270,9 @@ static void uart_close(struct tty_struct *tty, struct file *filp) 


	BUG_ON(!kernel_locked());



	if (!state)

		return;



	uport = state->uart_port;

	port = &state->port;
@@ -1316,9 +1319,9 @@ static void uart_close(struct tty_struct *tty, struct file *filp) 
	 */

	if (port->flags & ASYNC_INITIALIZED) {

		unsigned long flags;

		spin_lock_irqsave(&port->lock, flags);

		spin_lock_irqsave(&uport->lock, flags);

		uport->ops->stop_rx(uport);

		spin_unlock_irqrestore(&port->lock, flags);

		spin_unlock_irqrestore(&uport->lock, flags);

		/*

		 * Before we drop DTR, make sure the UART transmitter

		 * has completely drained; this is especially