Re: Don't let dwfl_linux_kernel_report_offline/find_elf go through build dir

[Josh Stone <jistone at redhat dot com>]

On 09/22/2009 03:22 AM, Mark Wielaard wrote:
> On Sun, 2009-09-20 at 21:04 -0700, Roland McGrath wrote:
>> I believe it was a specific feature request to have /lib/`uname -r`/build
>> get searched.  You'd have to ask around or look through old PRs for
>> systemtap to find the request.  But I'm not comfortable changing this right
>> now.  Keeping consistent with the depmod behavior is the sort of
>> excuse^H^H^H^H^H^Hstandard that I like, but we should take care to research
>> the past concerns of users before making a change.
> 
> I asked around and it is indeed a feature of stap:
> 
>    -r /DIR
>       Build for kernel in given build tree. Can also be set  with  the
>       SYSTEMTAP_RELEASE environment variable.
> 
>    -r RELEASE
>       Build  for kernel in build tree /lib/modules/RELEASE/build.  Can
>       also be set with the SYSTEMTAP_RELEASE environment variable.
> 
> So, that second case explicitly relies on searching the modules under
> the 'build' subdir.

I think the doc is a little misleading.  The second case is actually the
typical case, with a default of "-r $(uname -r)".  The build tree is
certainly in the build subdir (makefiles, headers, etc.), but the
modules are searched starting in /lib/modules/RELEASE/.

Could it be that we search .../build because of vmlinux?  If one makes a
custom kernel and does a "make modules_install", then all of the modules
get copied into /lib/modules/RELEASE/kernel/, but the unstripped,
uncompressed vmlinux is only available in the original build path.

Josh