Re: 2.6.9-rc2-mm3

From: Russell King
Date: Sat Sep 25 2004 - 04:21:16 EST


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
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