From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Darren Hart <dvhart@linux.intel.com>
Cc: Tomoya MORINAGA <tomoya.rohm@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Feng Tang <feng.tang@intel.com>,
Alexander Stein <alexander.stein@systec-electronic.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Cox <alan@linux.intel.com>,
linux-serial@vger.kernel.org
Subject: Re: [RFC PATCH] pch_uart: Add eg20t_port lock field, avoid recursive spinlocks
Date: Tue, 19 Jun 2012 18:54:32 +0100 [thread overview]
Message-ID: <20120619185432.30eb78c3@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <4FE0B853.5060203@linux.intel.com>
> I see, the oops_in_progress test right? My thinking was that the
> oops_in_progress was only relevant to the port.lock as that could be
> taken outside of the pch_uart driver, while the priv.lock is only used
> within the driver. But, as the oops uses the pch_console_write itself, I
> can see the recursive spinlock failure case there.
Until your driver crashes...
> As for the printk, it seems the 8250 driver would also suffer from that
> in the serial8250_console_write function on the port.lock, and it does
> not make any allowances for printk.
I think 8250 probably wants fixing too then!
>
> I would like to hold the priv.lock for a smaller window, but ordering
> requires that I take it prior to the port.lock.
>
> So I can test for oops_in_progress on the priv->lock too, but that won't
> address the printk issue. Is the oops the bigger concern?
the oops is the main one - a printk would have to be in driver as a
screwup, and you can force an oops on a stall so pick it up later
Alan
prev parent reply other threads:[~2012-06-19 17:51 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-31 8:54 [RFC PATCH] pch_uart: Add eg20t_port lock field, avoid recursive spinlocks Darren Hart
2012-06-01 8:30 ` Tomoya MORINAGA
2012-06-01 18:36 ` Darren Hart
2012-06-05 22:07 ` Darren Hart
2012-06-05 23:48 ` Tomoya MORINAGA
2012-06-18 21:41 ` Darren Hart
2012-06-18 22:21 ` Greg Kroah-Hartman
2012-06-19 9:14 ` Alan Cox
2012-06-19 17:35 ` Darren Hart
2012-06-19 17:54 ` Alan Cox [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120619185432.30eb78c3@pyramind.ukuu.org.uk \
--to=alan@lxorguk.ukuu.org.uk \
--cc=alan@linux.intel.com \
--cc=alexander.stein@systec-electronic.com \
--cc=dvhart@linux.intel.com \
--cc=feng.tang@intel.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=tomoya.rohm@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox