Re: 2.6.9-rc2-mm3

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Fri, Sep 24, 2004 at 10:25:11PM -0500, Paul Fulghum wrote:
> My suggestion was flawed in that it could
> violate POSIX requirements (as Russell pointed out).
> 
> Removing the lock from tty_termios_baud_rate(), tty_io.c
> corrects the problem for the path from change_termios()
> to tty_termios_baud_rate(), which is causing the deadlock.
> 
> This may not be, and probably is not,
> correct for all paths to tty_termios_baud_rate().

I wonder if we should consider adding:

	WARN_ON(!spin_is_locked(&tty_termios_lock));

in there.

However, the one annoying thing about "spin_is_locked" is that, on UP,
it defaults to "unlocked" which makes these kinds of checks too noisy.
Maybe we need a spin_is_locked() with a bias towards being locked for UP?

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core