From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Jiri Slaby <jslaby@suse.cz>
Cc: Jack Stone <jwjstone@fastmail.fm>, Mac <kmac@poczta.fm>,
linux-kernel@vger.kernel.org, linux-ppp@vger.kernel.org,
Greg Kroah-Hartman <gregkh@suse.de>,
Jiri Slaby <jirislaby@gmail.com>
Subject: Re: 'scheduling while atomic' during ppp connection on 2.6.37.1 and 2.6.38
Date: Thu, 31 Mar 2011 22:39:14 +0100 [thread overview]
Message-ID: <20110331223914.458a36b7@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <4D94E9E7.2050600@suse.cz>
> What is the proper way to avoid a race with HUP in tty->ops->write,
> chars_in_buffer, ntty_write_room and possibly others?
You shouldn't need to do anything in those cases as tty and
tty->driver_data won't be going anywhere. port->tty may go NULL and the
IRQ handlers etc need to get the refs properly and keep refs when needed
so the tty isn't freed under them, but that *should* be all that is
needed if the logic is right.
> I looked into the drivers, moxa tests tty->driver_data (why? [1]), mxser
> does nothing as well as rocket and many others. What is the reference
> driver I should look into?
I think its a delusion from early drivers that never got sorted
>
> [1] Perhaps leftover from when moxa_shutdown used to NULL it.
>
> I don't see why the driver should care at all. It has a tty,
> tty->driver_data and thus all the HW info. So it should ignore the race,
> i.e. test nothing, right?
Yes
next prev parent reply other threads:[~2011-03-31 21:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-19 22:06 Mac
2011-03-20 18:42 ` Jack Stone
2011-03-20 21:52 ` Jiri Slaby
2011-03-20 23:09 ` Jack Stone
2011-03-20 21:58 ` Alan Cox
2011-03-20 23:05 ` Jack Stone
2011-03-21 11:27 ` Alan Cox
2011-03-21 17:40 ` Jack Stone
2011-03-21 9:15 ` Jiri Slaby
2011-03-21 11:02 ` Alan Cox
2011-03-31 20:53 ` Jiri Slaby
2011-03-31 21:39 ` Alan Cox [this message]
-- strict thread matches above, loose matches on Subject: below --
2011-03-19 21:56 Mac
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