[FFmpeg-devel] gdb problem: Previous frame inner to this frame (gdb could not unwind past this frame)

Alexander Strange astrange
Sat Oct 23 21:12:20 CEST 2010

On Oct 23, 2010, at 2:47 PM, Jeff Crouse wrote:

> Hello ffmpeggers,
> I have a custom avfilter that essentially just loads in a shared
> object/library at runtime with init, process, and uninit functions.
> It's great because I don't have to recompile ffmpeg every time I make
> a change to my library. Then I just give the name to the library in
> the -vf argument.  Everything is working fine for the most part, but
> when I try to set a breakpoint in my library, GDB says:
> Previous frame inner to this frame (gdb could not unwind past this frame)
> And it just freezes up and doesn't give me a stack trace.  It's very
> frustrating because I can't debug my code.  I am using XCode 3.2.4 on
> a Macbook Pro, Mac OS X (10.6.4), with
> svn co -r 25296 svn://svn.ffmpeg.org/ffmpeg/trunk
> I'm not quite sure what other information to post, not how to start
> diagnosing this problem.  From my googling, the "gdb could not unwind
> past this frame" part of the error seems to be particular to Mac,
> although it is similar to an error that GDB throws when it thinks that
> the stack trace is corrupted.
> Has anyone seen this before?

You need to compile without -fomit-frame-pointer. This may involve configuring with --disable-asm, as otherwise the compiler tends to run out of registers.
It sounds like this is happening inside your own code, not ffmpeg's, though, so this isn't really an ffmpeg question.

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