From: Alexander Gordeev <lasaine@lvk.cs.msu.su>
To: Alan Cox <alan@linux.intel.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org,
"Nikita V\. Youshchenko" <yoush@cs.msu.su>,
linuxpps@ml.enneenne.com,
Rodolfo Giometti <giometti@enneenne.com>,
Greg Kroah-Hartman <gregkh@suse.de>,
Arnd Bergmann <arnd@arndb.de>, Al Viro <viro@zeniv.linux.org.uk>,
Nick Piggin <npiggin@kernel.dk>,
Jason Wessel <jason.wessel@windriver.com>,
Philippe Langlais <philippe.langlais@stericsson.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCHv5 05/17] tty: don't allow ldisc dcd_change() after ldisc halt
Date: Thu, 25 Nov 2010 16:30:35 +0300 [thread overview]
Message-ID: <20101125163035.3105747b@desktopvm.lvknet> (raw)
In-Reply-To: <20101124223600.5eb8476f@bob.linux.org.uk>
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В Wed, 24 Nov 2010 22:36:00 +0000
Alan Cox <alan@linux.intel.com> пишет:
> > Yes, indeed, it's a bug. Please consider the following example:
> >
> > CPU1 CPU2
> > =========================================================
> > uart_handle_dcd_change() { tty_set_ldisc() {
> > ld = tty_ldisc_ref(...) ...
>
> [We have a reference]
> > ... tty_ldisc_halt(...)
> [Should block]
>
> > I think tty code is exactly the right place to fix this bug; this is
> > what my patch is for.
>
> More special case magic on top of the current crap isn't the right fix
> here, tty_ldisc_halt needs to wait for the references to hit zero.
Didn't know that current design is crap. :)
Ok, I think I'll add a new waitqueue and a new bit (TTY_LDISC_NOREF)
that halt will wait for. Is it good?
--
Alexander
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next prev parent reply other threads:[~2010-11-25 13:31 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-24 16:15 [PATCHv5 00/17] pps: several fixes and improvements Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 01/17] pps: trivial fixes Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 02/17] pps: declare variables where they are used in switch Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 03/17] pps: fix race in PPS_FETCH handler Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 04/17] pps: unify timestamp gathering Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 05/17] tty: don't allow ldisc dcd_change() after ldisc halt Alexander Gordeev
2010-11-24 16:43 ` Alan Cox
2010-11-24 22:38 ` Alexander Gordeev
2010-11-24 22:36 ` Alan Cox
2010-11-25 13:30 ` Alexander Gordeev [this message]
2010-11-25 14:03 ` Alan Cox
2010-12-15 16:13 ` Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 06/17] pps: access pps device by direct pointer Alexander Gordeev
2010-12-16 15:52 ` Rodolfo Giometti
2010-12-16 21:58 ` Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 07/17] pps: convert printk/pr_* to dev_* Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 08/17] pps: move idr stuff to pps.c Alexander Gordeev
2010-12-16 15:53 ` Rodolfo Giometti
2010-11-24 16:15 ` [PATCHv5 09/17] pps: do not disable interrupts for idr operations Alexander Gordeev
2010-12-16 15:53 ` Rodolfo Giometti
2010-11-24 16:15 ` [PATCHv5 10/17] pps: use BUG_ON for kernel API safety checks Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 11/17] pps: simplify conditions a bit Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 12/17] pps: timestamp is always passed to dcd_change() Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 13/17] ntp: add hardpps implementation Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 14/17] pps: capture MONOTONIC_RAW timestamps as well Alexander Gordeev
2010-11-24 16:49 ` Thomas Gleixner
2010-11-25 9:55 ` Alexander Gordeev
2010-11-24 16:15 ` [PATCHv5 15/17] pps: add kernel consumer support Alexander Gordeev
2010-12-16 15:55 ` Rodolfo Giometti
2010-11-24 16:15 ` [PATCHv5 16/17] pps: add parallel port PPS client Alexander Gordeev
2010-12-16 15:58 ` Rodolfo Giometti
2010-11-24 16:15 ` [PATCHv5 17/17] pps: add parallel port PPS signal generator Alexander Gordeev
2010-12-16 16:02 ` Rodolfo Giometti
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