Re: [PATCH 1/3] Input: sysrq - drop tty argument from sysrq opshandlers

From: Benjamin Herrenschmidt
Date: Wed Aug 04 2010 - 04:34:38 EST

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

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.


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