From: greg@kroah.com (Greg KH)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Any successful story of debugging linux 4.13 with qemu 2.10 and gdb 8.01?
Date: Thu, 21 Sep 2017 09:21:43 +0200 [thread overview]
Message-ID: <20170921072143.GA4588@kroah.com> (raw)
In-Reply-To: <20170920192917.lg33kitgd4tqh4bx@judith.localdomain>
On Wed, Sep 20, 2017 at 09:29:17PM +0200, jjDaNiMoTh wrote:
> On 20/09/17 at 11:20am, ??? wrote:
> > 2017-09-20 4:18 GMT-04:00 jjDaNiMoTh <jjdanimoth@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.
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
next prev parent reply other threads:[~2017-09-21 7:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-20 8:18 Any successful story of debugging linux 4.13 with qemu 2.10 and gdb 8.01? jjDaNiMoTh
2017-09-20 15:20 ` 慕冬亮
2017-09-20 19:29 ` jjDaNiMoTh
2017-09-21 7:21 ` Greg KH [this message]
2017-09-21 7:29 ` Saket Sinha
2017-09-21 8:43 ` jjDaNiMoTh
2017-09-21 9:01 ` Greg KH
2017-09-21 17:08 ` 慕冬亮
2017-09-22 6:09 ` Saket Sinha
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