netdev - Re: Handling of EAGAIN from BPF verifier

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Date:   Mon, 7 Jan 2019 13:13:41 -0800
From:   Alexei Starovoitov <alexei.starovoitov@...il.com>
To:     Lorenz Bauer <lmb@...udflare.com>
Cc:     Alexei Starovoitov <ast@...nel.org>, netdev@...r.kernel.org,
        Daniel Borkmann <daniel@...earbox.net>
Subject: Re: Handling of EAGAIN from BPF verifier

On Mon, Jan 07, 2019 at 03:07:09PM +0000, Lorenz Bauer wrote:
> Hi,
> 
> Commit "bpf: check pending signals while verifying programs" makes the
> bpf syscall return EAGAIN for BPF_PROG_LOAD. How should user space
> react to this? The error sounds like it should retry, but I couldn't
> find the corresponding code for this in libbpf.

since the user process was suspended while loading the loader should retry.
I think libbpf should do it unconditionally in bpf_load_program_xattr().
Patches are welcome :)