------- Comment From heinz-werner_se...@de.ibm.com 2020-09-01 03:25 EDT-------
und BPF ist derzeit nicht mehr dringend, da arbeiten wir jetzt upstream, und 
werden zu einem sp?teren zeitpunt wiederkommen falls es ein target date gibt, 
aber das schreib ich dir noch in den LP

Status update from IBM : Currently this feature is not that urgend
anymore. Priorities have moved it to the right. But I will come back,
once this get in plan again and targetted ... Many thx for your support

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https://bugs.launchpad.net/bugs/1888507

Title:
  [UBUNTU 18.04] BPF programs fail on Ubuntu s390x

Status in Ubuntu on IBM z Systems:
  In Progress
Status in linux package in Ubuntu:
  New
Status in linux source package in Bionic:
  Triaged
Status in linux source package in Focal:
  In Progress

Bug description:
  [Impact]
  Some bpf programs will fail to execute on s390x, returning EFAULT when they 
should be able to read user memory.

  [Test case]
  apt-get source linux
  mkdir -p /usr/lib/perf/
  cp -a linux-5.4.0/tools/perf/include /usr/lib/perf/
  probe_read=$(grep -w probe_read /usr/lib/perf/include/bpf/bpf.h)
  probe_read_user=${probe_read//read/read_user}
  sed -i "/probe_read)/i$probe_read_user" /usr/lib/perf/include/bpf/bpf.h
  probe_read_user_str=${probe_read//read/read_user_str}
  sed -i "/probe_read)/i$probe_read_user_str" /usr/lib/perf/include/bpf/bpf.h

  ed - linux-5.4.0/tools/perf/examples/bpf/augmented_raw_syscalls.c << EOF
  100c
  int string_len = probe_read_user_str(&augmented_arg->value, arg_len, arg);
  .
  w
  EOF
  perf trace -eopenat,augmented_raw_syscalls.c cat /etc/passwd > /dev/null

  You should see:
       0.332 ( 0.002 ms): cat/3223 openat(dfd: CWD, filename: "/etc/passwd")    
                         = 3
  instead of
       0.334 ( 0.003 ms): cat/3739 openat(dfd: CWD, filename: "")               
                         = 3

  [Potential regressions]
  One potential regression is that unprivileged code can be able to exploit the 
changes to read or write kernel memory.


  --------------------------------------------------------------------------

  
  We need to run BPF filters to analyse and monitor network traffic. The BPF 
filters are created by skydive (http://skydive.network). Currently skydive 
fails to install BPF filters on s390x (using Ubuntu 18.04 currently, soon 
moving to Ubuntu 20.04).

  Because of these failures, we decided to try the BPF samples that come
  with the kernel first. These samples also fail on s390x while they
  work fine on Intel.

  shense@boe-build:~/bionic/samples/bpf$ uname -a
  Linux boe-build 4.15.0-112-generic #113-Ubuntu SMP Thu Jul 9 23:40:36 UTC 
2020 s390x s390x s390x GNU/Linux

  Example instructions:

  sudo apt install -y dpkg-dev clang llvm libelf-dev
  sudo apt-get source linux-image-unsigned-$(uname -r)
  cd linux-4.15.0/
  make headers_install
  make samples/bpf/

  Errors:

  shense@boe-build:~/bionic/samples/bpf$ sudo ./test_map_in_map
  [sudo] password for shense:
  invalid relo for insn[4].code 0x85
  bpf_load_program() err=22
  0: (bf) r7 = r1
  1: (b7) r1 = 0
  2: (63) *(u32 *)(r10 -32) = r1
  3: (bf) r1 = r7
  4: (85) call unknown#-1
  BPF_CALL uses reserved fields
  0: (bf) r7 = r1
  1: (b7) r1 = 0
  2: (63) *(u32 *)(r10 -32) = r1
  3: (bf) r1 = r7
  4: (85) call unknown#-1
  BPF_CALL uses reserved fields

  shense@boe-build:~/bionic/samples/bpf$ sudo ./map_perf_test
  invalid relo for insn[22].code 0x85
  bpf_load_program() err=22
  0: (bf) r7 = r1
  1: (18) r1 = 0x207265743a25646e
  3: (7b) *(u64 *)(r10 -16) = r1
  4: (18) r1 = 0x705f616c6c6f632e
  6: (7b) *(u64 *)(r10 -24) = r1
  7: (18) r1 = 0x5f6c72755f686d61
  9: (7b) *(u64 *)(r10 -32) = r1
  10: (18) r1 = 0x7420737472657373
  12: (7b) *(u64 *)(r10 -40) = r1
  13: (18) r1 = 0x4661696c65642061
  15: (7b) *(u64 *)(r10 -48) = r1
  16: (b7) r1 = 0
  17: (73) *(u8 *)(r10 -8) = r1
  18: (b7) r2 = 1
  19: (7b) *(u64 *)(r10 -72) = r2
  20: (63) *(u32 *)(r10 -76) = r1
  21: (bf) r1 = r7
  22: (85) call unknown#-1
  BPF_CALL uses reserved fields
  0: (bf) r7 = r1
  1: (18) r1 = 0x207265743a25646e
  3: (7b) *(u64 *)(r10 -16) = r1
  4: (18) r1 = 0x705f616c6c6f632e
  6: (7b) *(u64 *)(r10 -24) = r1
  7: (18) r1 = 0x5f6c72755f686d61
  9: (7b) *(u64 *)(r10 -32) = r1
  10: (18) r1 = 0x7420737472657373
  12: (7b) *(u64 *)(r10 -40) = r1
  13: (18) r1 = 0x4661696c65642061
  15: (7b) *(u64 *)(r10 -48) = r1
  16: (b7) r1 = 0
  17: (73) *(u8 *)(r10 -8) = r1
  18: (b7) r2 = 1
  19: (7b) *(u64 *)(r10 -72) = r2
  20: (63) *(u32 *)(r10 -76) = r1
  21: (bf) r1 = r7
  22: (85) call unknown#-1
  BPF_CALL uses reserved fields

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