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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jason Wessel <jason.wessel@windriver.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
	David Airlie <airlied@linux.ie>,
	David Miller <davem@davemloft.net>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Greg Kroah-Hartman <gregkh@suse.de>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Russell King <linux@arm.linux.org.uk>,
	Tony Luck <tony.luck@intel.com>
Subject: Re: [PATCH 1/3] Input: sysrq - drop tty argument from sysrq ops handlers
Date: Thu, 05 Aug 2010 12:03:05 +1000	[thread overview]
Message-ID: <1280973785.1902.167.camel@pasglop> (raw)
In-Reply-To: <4C59570F.7040201@windriver.com>

On Wed, 2010-08-04 at 07:03 -0500, Jason Wessel wrote:
> The usb serial has the same kind of problem with all sorts of locks.
> I
> had resorted to using a tasklet or workqueue to get the sysrq to
> execute
> just outside the usb serial driver context.  This work never made it
> upstream because it was part of another series, but the reference is:
> http://lkml.org/lkml/2010/3/9/17
> 
> For the standard serial you might be able to get away with dropping
> the
> lock for the sysrq.
> 
> Did you have a particular way to trigger the problem or was it just
> completely random, because I don't know that I have observed this
> behavior with the typical 8250 driver.

Yes, I do actually :-) A 64-way machine and a bunch of processes
flooding the console will do it just fine :-)

Cheers,
Ben.



  reply	other threads:[~2010-08-05  2:03 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-04  7:58 [PATCH 0/3] SysRq: do not pass tty argument around Dmitry Torokhov
2010-08-04  7:59 ` [PATCH 1/3] Input: sysrq - drop tty argument from sysrq ops handlers Dmitry Torokhov
2010-08-04  8:33   ` Benjamin Herrenschmidt
2010-08-04  9:09     ` Alan Cox
2010-08-05  1:59       ` Benjamin Herrenschmidt
2010-08-04 12:03     ` Jason Wessel
2010-08-05  2:03       ` Benjamin Herrenschmidt [this message]
2010-08-04  7:59 ` [PATCH 2/3] Input: sysrq - drop tty argument form handle_sysrq() Dmitry Torokhov
2010-08-04 11:25   ` Jason Wessel
2010-08-04  7:59 ` [PATCH 3/3] USB: drop tty argument from usb_serial_handle_sysrq_char() Dmitry Torokhov
2010-08-04 11:25   ` Jason Wessel
2010-08-04  9:11 ` [PATCH 0/3] SysRq: do not pass tty argument around Alan Cox
2010-08-04 19:44 ` Greg KH

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