Messages in this thread Patch in this message | | | Date | Tue, 09 Jun 2009 02:39:07 -0700 | From | Greg KH <> | Subject | [patch 19/87] Fix oops on close of hot-unplugged FTDI serial converter |
| |
2.6.29-stable review patch. If anyone has any objections, please let us know.
------------------
From: David Woodhouse <dwmw2@infradead.org>
commit 80193195f87ebca6d7417516d6edeb3969631c15 upstream.
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 <David.Woodhouse@intel.com> Tested-by: Daniel Mack <daniel@caiaq.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/usb/serial/ftdi_sio.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-)
--- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -1485,14 +1485,7 @@ static int ftdi_sio_port_remove(struct u 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; }
| |