From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: 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>,
Jason Wessel <jason.wessel@windriver.com>,
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: Wed, 04 Aug 2010 18:33:50 +1000 [thread overview]
Message-ID: <1280910830.1902.144.camel@pasglop> (raw)
In-Reply-To: <20100804075900.30647.46910.stgit@localhost.localdomain>
On Wed, 2010-08-04 at 00:59 -0700, Dmitry Torokhov wrote:
> Noone is using tty argument so let's get rid of it.
While talking about sysrq...
I noticed that serial drivers call sysrq with the uart lock held.
I've seen deadlocks caused by that, for example, when entering the
debugger, it waits forever for a CPU which is itself waiting on the UART
lock.
I have a patch to drop the lock in serial_core.h, I'll post that
tomorrow hopefully, just checking if there's any objection there ? The
serial drivers might need to be audited a bit to make sure they cope
with the lock being dropped and re-acquired around the sysrq call.
Cheers,
Ben.
next prev parent reply other threads:[~2010-08-04 8:34 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 [this message]
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
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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