netdev - Re: [bpf-next PATCH] bpf: libbpf, add kernel version section parsing back

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Message-ID: <4da33f52-e857-9997-4226-4eae0f440df9@fb.com>
Date:   Fri, 18 Oct 2019 16:51:43 +0000
From:   Andrii Nakryiko <andriin@...com>
To:     John Fastabend <john.fastabend@...il.com>,
        "ast@...nel.org" <ast@...nel.org>,
        "daniel@...earbox.net" <daniel@...earbox.net>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "bpf@...r.kernel.org" <bpf@...r.kernel.org>
Subject: Re: [bpf-next PATCH] bpf: libbpf, add kernel version section parsing
 back

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@...il.com>
> ---

In the name of not breaking users of weird kernels :)

Acked-by: Andrii Nakryiko <andriin@...com>

>   tools/lib/bpf/libbpf.c |   21 ++++++++++++++++++++-
>   1 file changed, 20 insertions(+), 1 deletion(-)
> 

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