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H A D | ftdi_sio.c | 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> 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>
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