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/openbmc/linux/drivers/usb/serial/
H A Dftdi_sio.c80193195 Mon May 18 07:07:35 CDT 2009 David Woodhouse <dwmw2@infradead.org> 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 <David.Woodhouse@intel.com>
Tested-by: Daniel Mack <daniel@caiaq.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
c45d6320 Thu Apr 30 09:06:19 CDT 2009 Alan Stern <stern@rowland.harvard.edu> usb-serial: ftdi_sio: fix reference counting of ftdi_private

This patch (as1238) adds proper reference counting for ftdi_sio's
private data structure. Without it, the driver will free the
structure while it is still in use if the user unplugs the serial
device before closing the device file.

The patch also replaces a slightly dangerous
cancel_delayed_work/flush_scheduled_work pair with
cancel_delayed_work_sync, which is always safer.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Daniel Mack <daniel@caiaq.de>
Tested-by: Daniel Mack <daniel@caiaq.de>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
80193195 Mon May 18 07:07:35 CDT 2009 David Woodhouse <dwmw2@infradead.org> 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 <David.Woodhouse@intel.com>
Tested-by: Daniel Mack <daniel@caiaq.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
c45d6320 Thu Apr 30 09:06:19 CDT 2009 Alan Stern <stern@rowland.harvard.edu> usb-serial: ftdi_sio: fix reference counting of ftdi_private

This patch (as1238) adds proper reference counting for ftdi_sio's
private data structure. Without it, the driver will free the
structure while it is still in use if the user unplugs the serial
device before closing the device file.

The patch also replaces a slightly dangerous
cancel_delayed_work/flush_scheduled_work pair with
cancel_delayed_work_sync, which is always safer.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Daniel Mack <daniel@caiaq.de>
Tested-by: Daniel Mack <daniel@caiaq.de>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>