From mboxrd@z Thu Jan  1 00:00:00 1970
From: ablacktshirt@gmail.com (Yubin Ruan)
Date: Fri, 20 Apr 2018 23:39:10 +0800
Subject: How can I disable compile optimization in kernel for friendly
 debugging, Thanks
In-Reply-To: <25804.1524158893@turing-police.cc.vt.edu>
References: <623d8297.8a0f.162dd208d7b.Coremail.sizel@163.com>
 <25804.1524158893@turing-police.cc.vt.edu>
Message-ID: <20180420153909.r3cjaytzmxnttswz@HP>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

On 2018-04-19 13:28, valdis.kletnieks at vt.edu wrote:
> On Thu, 19 Apr 2018 16:58:40 +0800, sizel said:
> >  How can I disable compile optimization in kernel for friendly  debugging, Thanks
> 
> First off, there are parts of the kernel that *WILL* explode if you try to build
> with -O0 - in particular, any code that expects static inlines to be treated as
> part of the unit they are inlined into for the purposes of __builtin_return_address()
> and similar.

Can you elaborate more on that?
 
> Second, modern gdb is perfectly able to deal with -O2 optimization,
> especially if you build with -g.  (In the kernel build, CONFIG_DEBUG_INFO=y
> will do the right thing for this).

I don't think so. According to my experience, GDB is not good enough to deal
with -O2 optimization.

Maybe my gdb is not modern enough? I am using gdb7.11 (Ubuntu 7.11.1-0ubuntu1~16.5)

Yubin