[lfs-dev] kernel orc unwinder

Bruce Dubbs bruce.dubbs at gmail.com
Wed Oct 18 19:49:10 PDT 2017

Ken Moffat wrote:
> One of the recent items in the kernel (new for 4.14) is the ORC
> stack unwinder, intended to get more accurate traces when a kernel
> dumps - so that people can work out what went wrong.
> It won't be the default for some time, but I'm trying it on my
> 4.14-rc kernel builds.  And now I've got to the end of LFS and
> failed to build the kernel, because this needs libelf :
> Makefile:937: *** "Cannot generate ORC metadata for CONFIG_ORC_UNWINDER=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel".  Stop.
> For as long as this is not the default, it will be like a lot of
> other things and only in BLFS.  But if it does become part of the
> default x86 config we will have to move it into LFS.

It sounds like something for kernel developers.  I cannot recall any 
kernel panics or other failures except occasionally when booting without 
the needed drivers.

I wonder if it would ever be set as the default and even if it is, it 
would be easier to just make a note that it should be disabled.

Of course, experienced lfsers would have no problem adding it via chroot.

   -- Bruce

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