Re: Linux-2.2.2-pre2..

Linus Torvalds (torvalds@transmeta.com)
Sun, 7 Feb 1999 11:55:06 -0800 (PST)


[ Thinking more about it ]

On Sun, 7 Feb 1999, Andrea Arcangeli wrote:
>
> When do_tty_hangup() runs current->lock_depth can be easily >=0 and we
> have the real spinlock unlocked so lock_kernel() does nothing and
> do_tty_hangup() can race fine with the other CPU that is holding the lock
> now.

Ahh, now I see your argument.

You are correct. The scheduler code is special, and the scheduler will
leave lock_depth set even though it has released the lock. I did that as a
performance optimization, because I thought nobody would ever care, but
it's obvious that yes, you do have to also set lock_depth to -1 inside the
scheduler.

Good point, sorry for not catching on to what you meant.

Linus

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