From: Paul Fulghum <paulkf@microgate.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Tim_T_Murphy@Dell.com, rmk+lkml@arm.linux.org.uk,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [BUG][2.6.8.1] serial driver hangs SMP kernel, but not the UP kernel
Date: Fri, 07 Jan 2005 08:04:12 -0600 [thread overview]
Message-ID: <41DE96DC.2090007@microgate.com> (raw)
In-Reply-To: <1105062326.17176.313.camel@localhost.localdomain>
Alan Cox wrote:
> On Gwe, 2005-01-07 at 00:43, Paul Fulghum wrote:
>
>>IIRC that guarantees a deadlock on SMP due to the
>>generic serial layer trying to grab a spinlock
>>that is already held. (Which prompted the original
>>bug report by Tim several months ago)
>
>
> I fixed the tty locking issues with that. If there are any left they
> should be solely in the serial generic code and I've no idea there
Yes, that is where the locking problems were.
When I last looked at it the problem call path was:
serial8250_interrupt();
spin_lock(port->lock);
serial8250_handle_port();
receive_chars();
flip.work.func(); /* if FLIP buffer full or low_latency set */
ldisc->receive_buf(); /* N_TTY */
tty->driver->flush_chars();
uart_start();
spin_lock(port->lock); *BANG*
--
Paul Fulghum
Microgate Systems, Ltd
next prev parent reply other threads:[~2005-01-07 14:09 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-06 22:47 [BUG][2.6.8.1] serial driver hangs SMP kernel, but not the UP kernel Tim_T_Murphy
2005-01-06 23:11 ` Alan Cox
2005-01-07 0:43 ` Paul Fulghum
2005-01-07 1:54 ` Alan Cox
2005-01-07 14:04 ` Paul Fulghum [this message]
-- strict thread matches above, loose matches on Subject: below --
2005-01-06 23:50 Tim_T_Murphy
2005-01-06 14:55 Tim_T_Murphy
2004-11-01 16:06 Tim_T_Murphy
2004-11-01 14:28 Tim_T_Murphy
2004-11-01 14:35 ` Russell King
2004-10-29 23:33 Tim_T_Murphy
2004-10-29 23:30 Tim_T_Murphy
2004-10-30 16:02 ` Russell King
2004-10-29 21:04 Tim_T_Murphy
2004-10-29 21:14 ` Russell King
2004-10-29 19:55 Tim_T_Murphy
2004-10-29 20:20 ` Russell King
2004-10-29 22:18 ` Paul Fulghum
2004-10-29 23:40 ` Paul Fulghum
2004-10-30 22:43 ` Alan Cox
2004-10-31 0:26 ` Paul Fulghum
2004-10-29 21:08 ` Paul Fulghum
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