From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: Regression due to d29f3ef "tty_lock: Localise the lock" Date: Tue, 8 May 2012 17:04:42 +0100 Message-ID: <20120508170442.409ccbe4@bob.linux.org.uk> References: <4FA8557E.5080402@wwwdotorg.org> <20120508103512.42db1c4b@pyramind.ukuu.org.uk> <4FA93FEB.2060200@wwwdotorg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FA93FEB.2060200-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stephen Warren Cc: Alan Cox , Greg Kroah-Hartman , Arnd Bergmann , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-tegra@vger.kernel.org On Tue, 08 May 2012 09:46:51 -0600 Stephen Warren wrote: > On 05/08/2012 03:35 AM, Alan Cox wrote: > > On Mon, 07 May 2012 17:06:38 -0600 > > Stephen Warren wrote: > > > >> Alan, > >> > >> Commit d29f3ef "tty_lock: Localise the lock" appears to cause a > >> problem for me. > >> > >> With this commit (as in next-20120507), I can no longer log into my > >> system (NVIDIA Tegra device with ARM CPU) over the serial console, > >> since the login prompt no longer appears. If I wait a few minutes, > >> I see the following console spew: > > > > Eep. If it's reproducable can you test whether adding the > > unlock/relock in drivers/tty/pty.c does the trick ? > > > > ie: > > tty_unlock(tty); > > tty_vhangup(tty); > > tty_lock(tty); > > Yes, that change in pty_close() solves the problem. Ok Greg - I think we should go with putting that unlock back until we understand exactly what is going on. Alan