netdev - Re: [PATCH bpf-next] selftests/bpf: fix -Wstrict-aliasing in test_sockopt

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Message-ID: <e676fc63-ec68-d6ed-8d66-5662b9abde49@iogearbox.net>
Date:   Sat, 29 Jun 2019 01:33:41 +0200
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Stanislav Fomichev <sdf@...gle.com>, netdev@...r.kernel.org,
        bpf@...r.kernel.org
Cc:     davem@...emloft.net, ast@...nel.org
Subject: Re: [PATCH bpf-next] selftests/bpf: fix -Wstrict-aliasing in
 test_sockopt_sk.c

On 06/28/2019 03:12 AM, Stanislav Fomichev wrote:
> Let's use union with u8[4] and u32 members for sockopt buffer,
> that should fix any possible aliasing issues.
> 
> test_sockopt_sk.c: In function ‘getsetsockopt’:
> test_sockopt_sk.c:115:2: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
>   if (*(__u32 *)buf != 0x55AA*2) {
>   ^~
> test_sockopt_sk.c:116:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
>    log_err("Unexpected getsockopt(SO_SNDBUF) 0x%x != 0x55AA*2",
>    ^~~~~~~
> 
> Fixes: 8a027dc0d8f5 ("selftests/bpf: add sockopt test that exercises sk helpers")
> Reported-by: Alexei Starovoitov <ast@...nel.org>
> Signed-off-by: Stanislav Fomichev <sdf@...gle.com>

Applied, thanks!