linux-kernel - Re: [PATCH 01/31] Add hard/soft lockup debugger entry points

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Message-ID: <alpine.DEB.2.11.1601282143110.3886@nanos>
Date:	Thu, 28 Jan 2016 21:48:13 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Jeffrey Merkey <jeffmerkey@...il.com>
cc:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	dzickus@...hat.com, uobergfe@...hat.com, atomlin@...hat.com,
	mhocko@...e.cz, fweisbec@...il.com, tj@...nel.org,
	hidehiro.kawai.ez@...achi.com, cmetcalf@...hip.com
Subject: Re: [PATCH 01/31] Add hard/soft lockup debugger entry points

On Thu, 28 Jan 2016, Jeffrey Merkey wrote:
> On 1/28/16, Thomas Gleixner <tglx@...utronix.de> wrote:
> > I'm probably missing something obvious here.
> 
> It's a pain in the butt to grep around through assembly language in a
> function in watchdog.c that has everything declared static with no
> symbols.  It's a lot easier just to insert an INT3 in the section of
> code that has the mouse caught in the trap (inside a function that
> triggers the hard lockup) -- after all -- that's what the instruction
> is for.

AFAICT, debuggers can set breakpoints on arbitrary code lines without grepping
through assembly language. If you don't have the debug information available,
then using a debugger is pointless anyway.

This is beyond silly. If we follow your argumentation we need another
gazillion of conditional breakpoints in the kernel. Definitely not.

Thanks,

	tglx