tree 71f7c39fda7d71980a64a5e1e35c08cf5c948820
parent 373f5aedbc6fb73d30f00eeb0dc7313ecfede908
author Alan Cox <alan@linux.intel.com> 1343408574 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1343415359 -0700

tty: Fix race in tty release

Ian Abbott found that the tty layer would explode with the right set of
parallel open and close operations. This is because we race in the
handling of tty->drivers->termios[].

Correct this by
	Making tty_ldisc_release behave like nromal code (takes the lock,
			does stuff, drops the lock)
	Drop the tty lock earlier in tty_ldisc_release
	Taking the tty mutex around the driver->termios update in all cases
	Adding a WARN_ON to catch future screwups.

I also forgot to clean up the pty resources properly. With a pty pair we
need to pull both halves out of the tables.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Tested-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>