Any successful story of debugging linux 4.13 with qemu 2.10 and gdb 8.01?

[jjDaNiMoTh]

On 20/09/17 at 11:20am, 慕冬亮 wrote:
> 2017-09-20 4:18 GMT-04:00 jjDaNiMoTh <jjdanimoth at gmail.com>:
> > Hello all,
> >
> > As the title says, any of you have successfully tried to debug Linux
> > 4.13 with QEMU?

> 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.

> But I found one interesting phenomenon:
> 
> If you try to "Ctrl + C" to stop the gdb when you see busybox is
> already working, you will see one special error:
> 
> Remote 'g' packet reply is too long:
[cut]

The answer to this issue is found easily on the internet. You have to
stop using -S, because it creates problems. Please take a look to [1].


Thanks for your reply and have a nice day!

JJD

[1] https://www.google.com/search?q=packet+reply+too+long+gdb+linux