netdev - Re: pull-request: bpf-next 2023-09-16

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Message-ID: <CANn89iKkEcsaEQRNmxdEHAkTbPVgVekUcjJvDsd-_fs0M9Qszw@mail.gmail.com>
Date: Mon, 18 Sep 2023 15:54:21 +0200
From: Eric Dumazet <edumazet@...gle.com>
To: Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc: Kumar Kartikeya Dwivedi <memxor@...il.com>, "David S. Miller" <davem@...emloft.net>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	Daniel Borkmann <daniel@...earbox.net>, Andrii Nakryiko <andrii@...nel.org>, 
	Network Development <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>, 
	Kernel Team <kernel-team@...com>
Subject: Re: pull-request: bpf-next 2023-09-16

On Mon, Sep 18, 2023 at 3:41 PM Alexei Starovoitov
<alexei.starovoitov@...il.com> wrote:
>
> On Mon, Sep 18, 2023 at 6:25 AM Eric Dumazet <edumazet@...gle.com> wrote:
> >
> > On Sat, Sep 16, 2023 at 6:59 PM Alexei Starovoitov
> > <alexei.starovoitov@...il.com> wrote:
> > >
> > > Hi David, hi Jakub, hi Paolo, hi Eric,
> > >
> > > The following pull-request contains BPF updates for your *net-next* tree.
> > >
> > > We've added 73 non-merge commits during the last 9 day(s) which contain
> > > a total of 79 files changed, 5275 insertions(+), 600 deletions(-).
> > >
> > > The main changes are:
> > >
> > > 1) Basic BTF validation in libbpf, from Andrii Nakryiko.
> > >
> > > 2) bpf_assert(), bpf_throw(), exceptions in bpf progs, from Kumar Kartikeya Dwivedi.
> > >
> > > 3) next_thread cleanups, from Oleg Nesterov.
> > >
> > > 4) Add mcpu=v4 support to arm32, from Puranjay Mohan.
> > >
> > > 5) Add support for __percpu pointers in bpf progs, from Yonghong Song.
> > >
> > > 6) Fix bpf tailcall interaction with bpf trampoline, from Leon Hwang.
> > >
> > > 7) Raise irq_work in bpf_mem_alloc while irqs are disabled to improve refill probabablity, from Hou Tao.
> > >
> > > Please consider pulling these changes from:
> > >
> > >   git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git
> > >
> >
> > This might have been raised already, but bpf on x86 now depends on
> > CONFIG_UNWINDER_ORC ?
> >
> > $ grep CONFIG_UNWINDER_ORC .config
> > # CONFIG_UNWINDER_ORC is not set
> >
> > $ make ...
> > arch/x86/net/bpf_jit_comp.c:3022:58: error: no member named 'sp' in
> > 'struct unwind_state'
> >                 if (!addr || !consume_fn(cookie, (u64)addr,
> > (u64)state.sp, (u64)state.bp))
> >                                                                  ~~~~~ ^
> > 1 error generated.
>
> Kumar,
> can probably explain better,
> but no the bpf as whole doesn't depend.
> One feature needs either ORC or frame unwinder.
> It won't work with unwinder_guess.
> The build error is a separate issue.
> It hasn't been reported before.

In my builds, I do have CONFIG_UNWINDER_FRAME_POINTER=y

$ grep UNWIND .config
# CONFIG_UNWINDER_ORC is not set
CONFIG_UNWINDER_FRAME_POINTER=y


I note state.sp is only available to CONFIG_UNWINDER_ORC

arch/x86/include/asm/unwind.h

#if defined(CONFIG_UNWINDER_ORC)
    bool signal, full_regs;
    unsigned long sp, bp, ip;
    struct pt_regs *regs, *prev_regs;
#elif defined(CONFIG_UNWINDER_FRAME_POINTER)
   bool got_irq;
   unsigned long *bp, *orig_sp, ip;   // this is orig_sp , not sp.
   ...