From: Stephen Hemminger <stephen@networkplumber.org>
To: madhukar mythri <madhukar.mythri@gmail.com>
Cc: users <users@dpdk.org>
Subject: Re: Failed to load eBPF byte-code on TAP device
Date: Thu, 16 Nov 2023 10:39:24 -0800 [thread overview]
Message-ID: <20231116103924.137be051@hermes.local> (raw)
In-Reply-To: <CAAUNki3w51pfA9_eBrs0NBuGroD6LDB+c_XW0TTPX1ZHXsh7Zw@mail.gmail.com>
On Thu, 16 Nov 2023 13:41:27 +0530
madhukar mythri <madhukar.mythri@gmail.com> wrote:
> Hi Stephen,
>
> I had added some logs in the BPF verifier of Kernel code, to print the
> number of instructions processed and error-code returned as follows:
> ============================
> logs # dmesg |tail -n 20
> [ 76.318101] #### do_check: instructions Processed 999989 insn
> [ 76.318102] #### do_check: instructions Processed 999990 insn
> [ 76.318103] #### do_check: instructions Processed 999991 insn
> [ 76.318104] #### do_check: instructions Processed 999992 insn
> [ 76.318105] #### do_check: instructions Processed 999993 insn
> [ 76.318106] #### do_check: instructions Processed 999994 insn
> [ 76.318107] #### do_check: instructions Processed 999995 insn
> [ 76.318108] #### do_check: instructions Processed 999996 insn
> [ 76.318109] #### do_check: instructions Processed 999997 insn
> [ 76.318110] #### do_check: instructions Processed 999998 insn
> [ 76.318111] #### do_check: instructions Processed 999999 insn
> [ 76.318112] #### do_check: instructions Processed 1000000 insn
> [ 76.318113] BPF program is too large. Processed 1000001 insn
> [ 76.318209] ########## bpf_check: do_check_main done..: ret: -7
> [ 76.318210] ########## bpf_check: bpf_prog_offload_finalize done..:
> ret: -7
> [ 76.318212] ########## bpf_check: check_max_stack_depth done..: ret: -7
> [ 76.318212] ########## bpf_check: fixup_call_args done..: ret: -7
> [ 76.318224] ########## bpf_check: end..: ret: -7
> [ 76.318224] ########## BPF bpf_check return err: -7..:
> =========================
>
> Only these logs which I add in the Kernel-code were printed and do not see
> any other Kernel-logs.
>
> Thanks,
> Madhuker.
>
> On Wed, Nov 15, 2023 at 8:49 PM Stephen Hemminger <
> stephen@networkplumber.org> wrote:
>
> > On Wed, 15 Nov 2023 15:38:55 +0530
> > madhukar mythri <madhukar.mythri@gmail.com> wrote:
> >
> > > Hi all,
> > >
> > > On the RHEL9.2 with DPDK 22.11.1 version, DPDK primary application failed
> > > to add RSS flow on TAP sub-device, when loading the TAP BPF byte-code
> > > instructions.
> > >
> > > This "struct bpf_insn l3_l4_hash_insns[]" array(from file:
> > > drivers/net/tap/tap_bpf_insns.h) is in eBPF bytecode instructions format,
> > > this eBPF failed to load on TAP PMD with the following error:
> > >
> > > =====================
> > > rss_add_actions(): Failed to load BPF section 'l3_l4' (7): Argument list
> > > too long.
> > > net_failsafe: Failed to create a flow on sub_device 1."
> > > =====================
> > > On Kernel-version: 5.15.0 #9 SMP PREEMPT
> > > Arch: x86_64 GNU/Linux
> > >
> > > When added some debug logs on Kernel BPF verifier code, we could see that
> > > instruction processed were reached to 1 Million.
> > > But, the Byte code has only 1698 instructions only. Why the Kernel BPF
> > > verifier is processing beyond 1,698 instructions ?
> > >
> > > The same byte-code(with DPDK-22.11.1) worked well with RHEL8.x and not
> > > working in RHEL-9.x version.
> > >
> > > Does anybody faced such issues ?
> > > Please let me know how to debug such issues on Byte-code.
> > >
> > > Thanks,
> > > Madhukar.
> >
> > Is there anything in the kernel log?
I suspect a kernel bug.
The kernel BPF API is not stable, and RHEL can and does modify the kernel.
Likely a Redhat bug.
Try with recent TAP fixes (in 23.11-rc3).
prev parent reply other threads:[~2023-11-16 18:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-15 10:08 madhukar mythri
2023-11-15 15:19 ` Stephen Hemminger
2023-11-16 8:11 ` madhukar mythri
2023-11-16 18:39 ` Stephen Hemminger [this message]
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