From mboxrd@z Thu Jan  1 00:00:00 1970
From: will.deacon@arm.com (Will Deacon)
Date: Wed, 14 Jun 2017 11:06:37 +0100
Subject: [PATCH 2/2] arm64: Export save_stack_trace_tsk()
In-Reply-To: <20170613181603.GE4902@n2100.armlinux.org.uk>
References: <20170613085029.GA5374@arm.com>
 <20170613173308.6653-1-dustinb@codeaurora.org>
 <20170613173308.6653-2-dustinb@codeaurora.org>
 <20170613174406.GH9184@arm.com>
 <20170613181603.GE4902@n2100.armlinux.org.uk>
Message-ID: <20170614100636.GA16190@arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Jun 13, 2017 at 07:16:03PM +0100, Russell King - ARM Linux wrote:
> On Tue, Jun 13, 2017 at 06:44:06PM +0100, Will Deacon wrote:
> > On Tue, Jun 13, 2017 at 10:33:08AM -0700, Dustin Brown wrote:
> > > To aid in debugging driver modules, export save_stack_trace_tsk() for
> > > the ARM64 architecture.
> > > ---
> > >  arch/arm64/kernel/stacktrace.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > 
> > Please can you repost with your Signed-off-by line added to the patch? I
> > can't merge anything from you without that.
> 
> I think it would also be a good thing to have a little more information
> about how this is being used in driver modules.

That would certainly help to motivate the change; I was just going by the
fact that most other architectures export this symbol and therefore it is
assumedly useful to somebody.

> If it's for ad-hoc debugging, then I see no reason for it to be merged
> into mainline kernels just for the utility of people adding code to
> drivers to perform that debug - they might as well temporarily add the
> export at the same time IMHO.

A quick look at the Debian archive suggests that it's used by "systemtap"
(although this seems to be part of an autoconf helper) and "kpatch".

Dustin -- do you have another use-case behind this?

Will