On Wed, Sep 20, 2017 at 09:29:17PM +0200, jjDaNiMoTh wrote:

On 20/09/17 at 11:20am, ??? wrote:

quoted

2017-09-20 4:18 GMT-04:00 jjDaNiMoTh [off-list ref]:

quoted

Hello all,

As the title says, any of you have successfully tried to debug Linux
4.13 with QEMU?

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I encountered this problem in my debian testing. Any "break" or
"hbreak" point is not triggered
even if I set breakpoint at "start_kernel".

[cut]

So, after two weeks of a headache I took the courage to send an email
here, and after only 3 hours after the email (!!!) I found the cause of
the problem.

Without being too long, the problem is KALSR. You have to disable it
disabling the kernel option "Randomize the address of the kernel image (KASLR)",
inside Processor type and features. In this way, gdb can translate
all the symbols correctly (symbols <-> addresses).

I really don't know how the developers test their code... because there
is no evidence for this.

Why do you think that it requires developers to use a debugger and qemu
to test their code?  I've never used a debugger on the kernel in all of
my years of kernel development...

Glad you found a solution and posted it.

greg k-h