On Thu, 16 Nov 2023 13:41:27 +0530 madhukar mythri <madhukar.myt...@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 < > step...@networkplumber.org> wrote: > > > On Wed, 15 Nov 2023 15:38:55 +0530 > > madhukar mythri <madhukar.myt...@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).
