Re: 3.4+ tty lockdep trace
From: Alan Cox
Date: Fri May 25 2012 - 06:46:37 EST
> Applying Ming's patch over Alan's 2 patches from yesterday, I'm still
> seeing two lockdep warnings. Full trace attached.
In that code path we've just succesfully done
tty_lock_pair(tty, o_tty)
(no warning issued)
We've then called into tty_ldisc_release which has done
tty_unlock_pair(tty, o_tty);
and then
tty_lock_pair(tty, o_tty);
which can't error unless our locking hosed
and at that point we then then do a recursive
tty_ldisc_release(o_tty, NULL)
which embarrassingly already has a comment above it I put there saying
/* This will need doing differently if we need to lock */
Let me go rewrite that particular routine to make sense with the
locking in place.
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