Alexei Starovoitov wrote:
> On Fri, Oct 18, 2019 at 9:52 AM Andrii Nakryiko <andriin@xxxxxx> wrote:
> >
> > On 10/18/19 7:41 AM, John Fastabend wrote:
> > > With commit "libbpf: stop enforcing kern_version,..." we removed the
> > > kernel version section parsing in favor of querying for the kernel
> > > using uname() and populating the version using the result of the
> > > query. After this any version sections were simply ignored.
> > >
> > > Unfortunately, the world of kernels is not so friendly. I've found some
> > > customized kernels where uname() does not match the in kernel version.
> > > To fix this so programs can load in this environment this patch adds
> > > back parsing the section and if it exists uses the user specified
> > > kernel version to override the uname() result. However, keep most the
> > > kernel uname() discovery bits so users are not required to insert the
> > > version except in these odd cases.
> > >
> > > Fixes: 5e61f27070292 ("libbpf: stop enforcing kern_version, populate it for users")
> > > Signed-off-by: John Fastabend <john.fastabend@xxxxxxxxx>
> > > ---
> >
> > In the name of not breaking users of weird kernels :)
> >
> > Acked-by: Andrii Nakryiko <andriin@xxxxxx>
>
> What does it mean that uname is cheated?
> Can libbpf read it from /proc/sys/kernel/osrelease ?
> or /proc/version?
> Is that read only or user space can somehow overwrite it?
In this case LINUX_VERSION_CODE as shown in version.h from linux-headers
does not much what is being reported by /proc/version or osrelease.
So its a bit surprising to me as well but I haven't got to the bottom
of it. Maybe something to do with how proc is mounted in this kubernetes
setup?
