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

[Sedat Dilek]

On Mon, Mar 22, 2021 at 10:02 AM Borislav Petkov <bp@xxxxxxx> wrote:
>
> On Mon, Mar 22, 2021 at 02:37:14PM +1100, Stephen Rothwell 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>
> > ---
> >  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;
> >       }
> >
> > --
>
> I guess we can do the same as with the hyperv tree - the folks who send the
> respective branches to Linus in the next merge window should point to this patch
> of yours which Linus can apply after merging the second branch in order.
>
> Thx.
>

The commit b90829704780 "bpf: Use NOP_ATOMIC5 instead of
emit_nops(&prog, 5) for BPF_TRAMP_F_CALL_ORIG" is now in Linus Git
(see [1]).

Where will Stephen's fixup-patch be carried?
Linux-next?
net-next?
<tip.git#x86/cpu>?

Thanks.

- Sedat -

[1] https://git.kernel.org/linus/b9082970478009b778aa9b22d5561eef35b53b63