From: Pedro Alves <pedro@codesourcery.com>
To: gdb@sourceware.org
Cc: zhihua che <zhihua.che@gmail.com>
Subject: Re: How "can't compute CFA for this frame" and "no enough registers or memory available to further unwind" happen?
Date: Mon, 31 Oct 2011 20:54:00 -0000 [thread overview]
Message-ID: <201110311743.03721.pedro@codesourcery.com> (raw)
In-Reply-To: <CABexPfGFMUgzjRZ22nsB=A2RoQk2oYORHA+E2cX2y6=bU+Hgjw@mail.gmail.com>
On Monday 31 October 2011 17:25:46, zhihua che wrote:
> Hi, everyone
>
> I'm not sure this is right place for the help. I'm writing a
> toy os and coding with mixed assembly and C language, debugging with
> GDB. But I'm trapped with an annoying problem. This is my situation:
> During the os booting time, after the os control transfers from real
> mode assembly codes to real mode C codes, I wish I can exam the stack
> frames and local variable as I do in regular application program, but
> I always get "can't compute CFA for this frame" or "No enough
> registers or memory available to further unwind" if I issue "print
> xxx" or "backtrace" command respectivelly.
You'll need to debug gdb. Check what is it that gdb is finding
unavailable. Put a breakpoint at `throw_error' and then do that
"print XXX". You should hit a call like `throw_error (NOT_AVAILABLE_ERROR...'.
Get a backtrace. Do "continue" on the top gdb, and see if further
hits appear. GDB has an exception handling mechanism, and that
exception may be thrown more than once during a command run.
> The codes seem work, but I
> can only exam registers or memory using "info reg" or "x" command,
> it's way unfriendly and time-consuming. I have searched a lot but
> don't figure out how these happen. I need your help. Thanks.
What's the output of "info all-registers"?
--
Pedro Alves
next prev parent reply other threads:[~2011-10-31 17:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-31 17:43 zhihua che
2011-10-31 20:54 ` Pedro Alves [this message]
[not found] ` <CABexPfH0HLsP1mR2oxR1HfSxOUkULL6pErB2QiVfR0es+G=qqw@mail.gmail.com>
2011-10-31 21:35 ` Fwd: " zhihua che
[not found] ` <201110311946.50273.pedro@codesourcery.com>
2011-10-31 21:36 ` zhihua che
[not found] ` <CABexPfFbrt6hv5fBvXMYXxVCaD_x7KFvUq-DV1X8EvWQaVsonQ@mail.gmail.com>
[not found] ` <CABexPfEFdc10NEVtJREy6NoryHNXFWt55+kMHoKpqO_ggQKvOg@mail.gmail.com>
2011-11-01 11:58 ` zhihua che
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