Re: linux-next: build failure after merge of the tip tree

[Sedat Dilek]

On Mon, Mar 22, 2021 at 4:39 AM Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> Hi all,
>
> After merging the tip tree, today's linux-next build (x86_64 allmodconfig)
> failed like this:
>
> arch/x86/net/bpf_jit_comp.c: In function 'arch_prepare_bpf_trampoline':
> arch/x86/net/bpf_jit_comp.c:2015:16: error: 'ideal_nops' undeclared (first use in this function)
>  2015 |   memcpy(prog, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE);
>       |                ^~~~~~~~~~
> arch/x86/net/bpf_jit_comp.c:2015:16: note: each undeclared identifier is reported only once for each function it appears in
> arch/x86/net/bpf_jit_comp.c:2015:27: error: 'NOP_ATOMIC5' undeclared (first use in this function); did you mean 'GFP_ATOMIC'?
>  2015 |   memcpy(prog, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE);
>       |                           ^~~~~~~~~~~
>       |                           GFP_ATOMIC
>
> Caused by commit
>
>   a89dfde3dc3c ("x86: Remove dynamic NOP selection")
>
> interacting with commit
>
>   b90829704780 ("bpf: Use NOP_ATOMIC5 instead of emit_nops(&prog, 5) for BPF_TRAMP_F_CALL_ORIG")
>
> from the net tree.
>
> I have applied the following merge fix patch.
>
> From: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Date: Mon, 22 Mar 2021 14:30:37 +1100
> Subject: [PATCH] x86: fix up for "bpf: Use NOP_ATOMIC5 instead of
>  emit_nops(&prog, 5) for BPF_TRAMP_F_CALL_ORIG"
>
> Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>

I had the same issue yesterday, when I had...

<tip.git#x86/cpu> + <net.git#master>

...on top of Linux v5.12-rc4.
( See [1] and [2] ).

I applied the same fix.

- Sedat -

[1] https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?h=x86/cpu&id=a89dfde3dc3c2dbf56910af75e2d8b11ec5308f6
[2] https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=b9082970478009b778aa9b22d5561eef35b53b63

> ---
>  arch/x86/net/bpf_jit_comp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
> index db50ab14df67..e2b5da5d441d 100644
> --- a/arch/x86/net/bpf_jit_comp.c
> +++ b/arch/x86/net/bpf_jit_comp.c
> @@ -2012,7 +2012,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
>                 /* remember return value in a stack for bpf prog to access */
>                 emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
>                 im->ip_after_call = prog;
> -               memcpy(prog, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE);
> +               memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
>                 prog += X86_PATCH_SIZE;
>         }
>
> --
> 2.30.0
>
> --
> Cheers,
> Stephen Rothwell