From: Hollis Blanchard <hollisb@us.ibm.com>
To: Alan <alan@lxorguk.ukuu.org.uk>
Cc: Jiri Slaby <jirislaby@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
p.hardwick@option.com
Subject: Re: tty->low_latency + irq context
Date: Tue, 02 Jan 2007 13:36:01 -0600 [thread overview]
Message-ID: <1167766562.5616.29.camel@basalt> (raw)
In-Reply-To: <20070102183829.10d861fc@localhost.localdomain>
On Tue, 2007-01-02 at 18:38 +0000, Alan wrote:
> > with tty->low_latency set, but it doesn't AFAICS. One possibility
> for
> > deadlock is if the tty->buf.lock spinlock is taken on behalf of a
> user
> > process...
>
> The case to watch out for is
>
> flip_buffer_push -> ldisc -> driver write of echo/^S/^Q
>
> if you call flip_buffer_push while holding your own lock you may get
> in a mess on the echo path.
Agreed. However, that's not what the comment says:
* tty_flip_buffer_push - terminal
* @tty: tty to push
*
* Queue a push of the terminal flip buffers to the line discipline. This
* function must not be called from IRQ context if tty->low_latency is set.
--
Hollis Blanchard
IBM Linux Technology Center
prev parent reply other threads:[~2007-01-02 19:36 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-26 0:09 tty->low_latency + irq context Jiri Slaby
2007-01-02 17:17 ` Hollis Blanchard
2007-01-02 18:12 ` Paul Fulghum
2007-01-02 18:29 ` Paul Fulghum
2007-01-02 18:38 ` Alan
2007-01-02 19:36 ` Hollis Blanchard [this message]
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