From: Alan Cox <alan@linux.intel.com>
To: Sasha Levin <levinsasha928@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Dave Jones <davej@redhat.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: 3.4+ tty lockdep trace
Date: Fri, 25 May 2012 12:02:16 +0100 [thread overview]
Message-ID: <20120525120216.45381ec6@bob.linux.org.uk> (raw)
In-Reply-To: <CA+1xoqemV-zsM3wZKDrirNopqVoH7PbHKijFCGQK2HuSDAN+CA@mail.gmail.com>
> 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.
prev parent reply other threads:[~2012-05-25 10:46 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-23 0:26 3.4+ tty lockdep trace Dave Jones
2012-05-23 1:06 ` Ming Lei
2012-05-23 1:17 ` Dave Jones
2012-05-23 2:02 ` Dave Jones
2012-05-23 2:44 ` Ming Lei
2012-05-23 23:05 ` Alan Cox
2012-05-24 6:13 ` Sasha Levin
2012-05-24 11:10 ` Alan Cox
2012-05-24 11:20 ` Sasha Levin
2012-05-24 11:21 ` Sasha Levin
2012-05-24 11:24 ` Sasha Levin
2012-05-24 14:54 ` Alan Cox
2012-05-25 2:32 ` Steven Rostedt
2012-05-25 8:07 ` Sasha Levin
2012-05-25 8:30 ` Ming Lei
2012-05-25 10:24 ` Sasha Levin
2012-05-25 11:02 ` Alan Cox [this message]
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