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

From: Thomas Gleixner
Date: Thu Jan 28 2016 - 14:58:05 EST

On Thu, 28 Jan 2016, Jeffrey Merkey wrote:

> This patch series adds an export which can be set by system debuggers to
> direct the hard lockup and soft lockup detector to trigger a breakpoint
> exception and enter a debugger if one is active. It is assumed that if
> someone sets this variable, then an breakpoint handler of some sort will
> be actively loaded or registered via the notify die handler chain.
> This addition is extremely useful for debugging hard and soft lockups
> real time and quickly from a console debugger.

Why do we need an extra breakpoint instruction in the code to enter a
debugger? Don't have debuggers mechanisms to install breakpoints?

I'm probably missing something obvious here.