kernel configuration and installation

DJ Lucas dj at
Thu Oct 30 16:11:39 PDT 2008

Richard Melville wrote:
>>  Yes, I think you've missed the important thing ;)  The kernel
>> headers are what glibc was compiled against, and they should not be
>> changed unless you upgrade glibc [ and before anyone misconstrues
>> that, we *don't* support upgrading glibc - when the time comes,
>> build a new system ].
> Hi Ken
> My reading of Rob's post was that he was wondering why distros like
> Ubuntu could frequently update kernel headers when we are told not to. 
> If this was not his question then I wouldn't mind some advise on this issue.
> The problem occurs when some packages insist on parsing
> /usr/include/linux.  I had a problem recently when installing VLC.  I
> had enabled DCCP in my new kernel and I wanted to build VLC with the
> required support. I had already tested DCCP and it was working OK, but
> the VLC build failed complaining about missing headers.  When I checked
> the source code it was looking in /usr/include/linux, which surely must
> be bad practice.  

No. Not bad practice, that is why we 'sanitize' the kernel headers for 
use in userspace.  VLC, however, should be looking for its own copy of 
the kernel headers if it requires a particular version (see below).

> I can't see why arbitrary packages should be poking
> around in the kernel headers.  Clearly, as my glibc was built against
> much older kernel headers its search was unsuccessful.
> I was wondering what the solution is here?  Should we install the new
> kernel headers into a separate sub-directory and change the source code
> to point to the new sub-directory rather than to /usr/include/linux, or
> would this just not work?

According to the kernel devs, or at least last time I _heard_ (hearsay) 
anything about the subject, the answer was that the VLC maintainers 
failed to include the necessary kernel headers in the distribution 
tarball and provide a runtime check of the kernel for the necessary 
feature(s).  I'm not certain if this is still current practice, and 
would appreciate a confirmation on that.

-- DJ Lucas

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