From 80193195f87ebca6d7417516d6edeb3969631c15 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Mon, 18 May 2009 13:07:35 +0100 Subject: [PATCH] Fix oops on close of hot-unplugged FTDI serial converter Commit c45d6320 ("fix reference counting of ftdi_private") stopped ftdi_sio_port_remove() from directly freeing the port-private data, with the intention if the port was still open, it would be freed when ftdi_close() is eventually called and releases the last refcount on the structure. That's all very well, but ftdi_sio_port_remove() still contains a call to usb_set_serial_port_data(port, NULL) -- so by the time we get to ftdi_close() for the port which was unplugged, it _still_ oopses on dereferencing that NULL pointer, as it did before (and does in 2.6.29). The fix is just not to clear the private data in ftdi_sio_port_remove(). Then the refcount is properly reduced to zero when the final kref_put() happens in ftdi_close(). Remove a bogus comment too, while we're at it. And stop doing things inside "if (priv)" -- it must _always_ be there. Based loosely on an earlier patch by Daniel Mack, and suggestions by Alan Stern. Signed-off-by: David Woodhouse Tested-by: Daniel Mack Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- drivers/usb/serial/ftdi_sio.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 0ab8474b00cb..d9fcdaedf389 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -1487,14 +1487,7 @@ static int ftdi_sio_port_remove(struct usb_serial_port *port) remove_sysfs_attrs(port); - /* all open ports are closed at this point - * (by usbserial.c:__serial_close, which calls ftdi_close) - */ - - if (priv) { - usb_set_serial_port_data(port, NULL); - kref_put(&priv->kref, ftdi_sio_priv_release); - } + kref_put(&priv->kref, ftdi_sio_priv_release); return 0; } -- 2.20.1