linux-toradex.git/drivers/tty/pty.c, branch v3.7

pty: Fix locking bug on error path

2012-09-21T16:51:09+00:00

We end up dropping the mutex twice on some errors. We don't want to do
that.

Reported-by: Fengguang Wu 
Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

TTY: tty_alloc_driver() returns error pointers

2012-08-16T19:07:23+00:00

We changed these from alloc_tty_driver() to tty_alloc_driver() so the
error handling needs to modified to check for IS_ERR() instead of NULL.

Signed-off-by: Dan Carpenter 
Acked-by: Jiri Slaby 
Signed-off-by: Greg Kroah-Hartman

TTY: pty, switch to tty_alloc_driver

2012-08-13T23:45:38+00:00

Switch to the new driver allocation interface, as this is one of the
special call-sites. Here, we need TTY_DRIVER_DYNAMIC_ALLOC to not
allocate tty_driver->ports, cdevs and potentially other structures
because we reserve too many lines in pty. Instead, it provides the
tty_port<->tty_struct link in tty->ops->install already.

Signed-off-by: Jiri Slaby 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

TTY: pty, stop passing NULL to free_tty_struct

2012-08-10T20:27:50+00:00

In case alloc_tty_struct fails in pty_common_install, we pass NULL to
free_tty_struct. This is invalid as the function is not ready to cope
with that. And even if it was, it is not nice to do that anyway.

Signed-off-by: Jiri Slaby 
Reported-by: Dan Carpenter 
Signed-off-by: Greg Kroah-Hartman

tty: localise the lock

2012-08-10T19:55:47+00:00

The termios and other changes mean the other protections needed on the driver
tty arrays should be adequate. Turn it all back on.

This contains pieces folded in from the fixes made to the original patches

| From: Geert Uytterhoeven 	(fix m68k)
| From: Paul Gortmaker 	(fix cris)
| From: Jiri Kosina 			(lockdep)
| From: Eric Dumazet 		(lockdep)

Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty: Fix race in tty release

2012-07-27T18:55:59+00:00

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 
Tested-by: Ian Abbott 
Signed-off-by: Greg Kroah-Hartman

tty: Move the handling of the tty release logic

2012-07-17T16:13:38+00:00

Now that we don't have tty->termios tied to drivers->tty we can untangle
the logic here. In addition we can push the removal logic out of the
destructor path.

At that point we can think about sorting out tty_port and console and all
the other ugly hangovers.

Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty: move the termios object into the tty

2012-07-16T20:00:41+00:00

This will let us sort out a whole pile of tty related races. The
alternative would be to keep points and refcount the termios objects.
However
1. They are tiny anyway
2. Many devices don't use the stored copies
3. We can remove a pty special case

Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty: revert incorrectly applied lock patch

2012-07-16T19:58:12+00:00

I sent GregKH this after the pre-requisites. He dropped the pre-requesites
for good reason and unfortunately then applied this patch. Without this
reverted you get random kernel memory corruption which will make bisecting
anything between it and the properly applied patches a complete sod.

Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty: double unlock on error in ptmx_open()

2012-07-12T21:27:08+00:00

The problem here is that we called mutex_unlock(&devpts_mutex) on the
error path when we weren't holding the lock.

Signed-off-by: Dan Carpenter 
Signed-off-by: Greg Kroah-Hartman