linux-stable/tools/testing/selftests/bpf
Daniel Borkmann d7a5091351 bpf: Update selftests to reflect new error states
Update various selftest error messages:

 * The 'Rx tried to sub from different maps, paths, or prohibited types'
   is reworked into more specific/differentiated error messages for better
   guidance.

 * The change into 'value -4294967168 makes map_value pointer be out of
   bounds' is due to moving the mixed bounds check into the speculation
   handling and thus occuring slightly later than above mentioned sanity
   check.

 * The change into 'math between map_value pointer and register with
   unbounded min value' is similarly due to register sanity check coming
   before the mixed bounds check.

 * The case of 'map access: known scalar += value_ptr from different maps'
   now loads fine given masks are the same from the different paths (despite
   max map value size being different).

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
2021-04-16 23:52:15 +02:00
..
benchs bpf/benchs/bench_ringbufs: Remove unneeded semicolon 2021-02-08 13:41:24 -08:00
bpf_testmod selftests: bpf: Add a new test for bare tracepoints 2021-01-20 14:14:05 -08:00
gnu
map_tests
prog_tests bpf/selftests: Test that kernel rejects a TCP CC with an invalid license 2021-03-26 17:51:02 +01:00
progs bpf/selftests: Test that kernel rejects a TCP CC with an invalid license 2021-03-26 17:51:02 +01:00
verifier bpf: Update selftests to reflect new error states 2021-04-16 23:52:15 +02:00
.gitignore selftests/bpf: Integrate the socket_cookie test to test_progs 2021-02-11 17:44:41 -08:00
bench.c selftests: Remove fmod_ret from test_overhead 2020-09-28 17:20:28 -07:00
bench.h
bpf_legacy.h selftests: bpf: Remove unused bpf_map_def_legacy struct 2020-07-08 01:33:14 +02:00
bpf_rand.h
bpf_rlimit.h
bpf_sockopt_helpers.h bpf: Enable bpf_{g,s}etsockopt in BPF_CGROUP_UDP{4,6}_SENDMSG 2021-01-29 02:09:05 +01:00
bpf_tcp_helpers.h bpf: selftests: Add non function pointer test to struct_ops 2021-02-12 11:49:36 -08:00
bpf_util.h
btf_helpers.c selftests/bpf: Add split BTF dedup selftests 2020-11-05 18:37:31 -08:00
btf_helpers.h selftests/bpf: Add split BTF dedup selftests 2020-11-05 18:37:31 -08:00
cgroup_helpers.c bpf, selftests: Use single cgroup helpers for both test_sockmap/progs 2020-08-01 20:20:59 -07:00
cgroup_helpers.h bpf, selftests: Use single cgroup helpers for both test_sockmap/progs 2020-08-01 20:20:59 -07:00
config selftests/bpf: Add config dependency on BLK_DEV_LOOP 2020-12-03 11:20:21 -08:00
flow_dissector_load.c
flow_dissector_load.h selftests/bpf: Don't use deprecated libbpf APIs 2020-09-03 17:14:40 -07:00
get_cgroup_id_user.c bpf, selftests: Use single cgroup helpers for both test_sockmap/progs 2020-08-01 20:20:59 -07:00
ima_setup.sh selftests/bpf: Silence ima_setup.sh when not running in verbose mode. 2020-12-10 22:14:32 -08:00
Makefile selftests/bpf: Integrate the socket_cookie test to test_progs 2021-02-11 17:44:41 -08:00
netcnt_common.h
network_helpers.c bpf: selftests: Add fastopen_connect to network_helpers 2020-08-24 14:35:00 -07:00
network_helpers.h bpf: selftests: Add fastopen_connect to network_helpers 2020-08-24 14:35:00 -07:00
README.rst bpf/selftests: Add a short note about vmtest.sh in README.rst 2021-02-04 16:03:16 -08:00
settings selftests: bpf: Switch off timeout 2020-08-06 16:57:05 -07:00
test_bpftool.py
test_bpftool.sh
test_bpftool_build.sh selftests, bpftool: Add bpftool (and eBPF helpers) documentation build 2020-09-10 11:02:45 -07:00
test_bpftool_metadata.sh selftests/bpf: Test load and dump metadata with btftool and skel 2020-09-15 18:28:27 -07:00
test_btf.h
test_cgroup_storage.c bpf: Rename BPF_XADD and prepare to encode other atomics in .imm 2021-01-14 18:34:29 -08:00
test_cpp.cpp
test_dev_cgroup.c bpf, selftests: Use single cgroup helpers for both test_sockmap/progs 2020-08-01 20:20:59 -07:00
test_flow_dissector.c selftests/bpf: Remove unneeded semicolon 2021-02-08 17:54:24 -08:00
test_flow_dissector.sh
test_ftrace.sh
test_iptunnel_common.h
test_kmod.sh selftests: bpf: test_kmod.sh: Fix running out of srctree 2020-07-21 13:26:24 -07:00
test_lirc_mode2.sh
test_lirc_mode2_user.c
test_lpm_map.c
test_lru_map.c
test_lwt_ip_encap.sh
test_lwt_seg6local.sh selftests/bpf: Fix test_lwt_seg6local.sh hangs 2020-07-21 13:26:26 -07:00
test_maps.c selftests/bpf: Work-around EBUSY errors from hashmap update/delete 2020-12-24 01:35:46 +01:00
test_maps.h
test_netcnt.c bpf, selftests: Use single cgroup helpers for both test_sockmap/progs 2020-08-01 20:20:59 -07:00
test_offload.py Kbuild updates for v5.11 2020-12-22 14:02:39 -08:00
test_progs.c selftests/bpf: Don't exit on failed bpf_testmod unload 2021-01-26 17:02:00 +01:00
test_progs.h bpf: Remove extra lock_sock for TCP_ZEROCOPY_RECEIVE 2021-01-20 14:23:00 -08:00
test_select_reuseport_common.h
test_skb_cgroup_id.sh
test_skb_cgroup_id_user.c bpf, selftests: Use single cgroup helpers for both test_sockmap/progs 2020-08-01 20:20:59 -07:00
test_sock.c bpf, selftests: Use single cgroup helpers for both test_sockmap/progs 2020-08-01 20:20:59 -07:00
test_sock_addr.c selftests/bpf: Rewrite recvmsg{4,6} asm progs to c in test_sock_addr 2021-01-29 02:09:05 +01:00
test_sock_addr.sh
test_sockmap.c selftests/bpf: Fix invalid use of strncat in test_sockmap 2020-12-03 18:07:05 -08:00
test_stub.c
test_sysctl.c bpf, selftests: Use single cgroup helpers for both test_sockmap/progs 2020-08-01 20:20:59 -07:00
test_tag.c
test_tc_edt.sh
test_tc_redirect.sh bpf, selftests: Extend test_tc_redirect to use modified bpf_redirect_neigh() 2020-10-22 01:30:00 +02:00
test_tc_tunnel.sh
test_tcp_check_syncookie.sh
test_tcp_check_syncookie_user.c
test_tcp_hdr_options.h bpf: selftest: Ensure the child sk inherited all bpf_sock_ops_cb_flags 2020-10-02 11:34:48 -07:00
test_tcpbpf.h selftests/bpf: Add Userspace tests for TCP_WINDOW_CLAMP 2020-12-03 17:23:24 -08:00
test_tcpnotify.h
test_tcpnotify_user.c bpf: Fix compilation warning of selftests 2020-08-06 16:58:42 -07:00
test_tunnel.sh selftest/bpf: Add missed ip6ip6 test back 2020-11-10 15:37:45 -08:00
test_verifier.c selftest/bpf: Testing for multiple logs on REJECT 2021-02-03 22:01:25 +01:00
test_verifier_log.c
test_xdp_meta.sh
test_xdp_redirect.sh selftests/bpf: Convert test_xdp_redirect.sh to bash 2021-02-11 16:28:02 +01:00
test_xdp_veth.sh
test_xdp_vlan.sh
test_xdp_vlan_mode_generic.sh
test_xdp_vlan_mode_native.sh
test_xdping.sh
test_xsk.sh selftests/bpf: Xsk selftests - Bi-directional Sockets - SKB, DRV 2020-12-09 16:44:45 +01:00
testing_helpers.c selftests/bpf: Add link detach tests for cgroup, netns, and xdp bpf_links 2020-08-01 20:38:28 -07:00
testing_helpers.h selftests/bpf: Add link detach tests for cgroup, netns, and xdp bpf_links 2020-08-01 20:38:28 -07:00
trace_helpers.c selftests/bpf: Ksyms_btf to test typed ksyms 2020-10-02 14:59:25 -07:00
trace_helpers.h selftests/bpf: Ksyms_btf to test typed ksyms 2020-10-02 14:59:25 -07:00
urandom_read.c
vmtest.sh bpf: Helper script for running BPF presubmit tests 2021-02-04 16:03:16 -08:00
with_addr.sh
with_tunnels.sh
xdping.c
xdping.h
xdpxceiver.c selftests/bpf: Simplify the calculation of variables 2021-02-10 12:14:27 -08:00
xdpxceiver.h selftests/bpf: Remove unused enums 2021-01-26 00:05:01 +01:00
xsk_prereqs.sh selftests/bpf: Xsk selftests - SKB POLL, NOPOLL 2020-12-09 16:44:45 +01:00

==================
BPF Selftest Notes
==================
General instructions on running selftests can be found in
`Documentation/bpf/bpf_devel_QA.rst`__.

__ /Documentation/bpf/bpf_devel_QA.rst#q-how-to-run-bpf-selftests

=========================
Running Selftests in a VM
=========================

It's now possible to run the selftests using ``tools/testing/selftests/bpf/vmtest.sh``.
The script tries to ensure that the tests are run with the same environment as they
would be run post-submit in the CI used by the Maintainers.

This script downloads a suitable Kconfig and VM userspace image from the system used by
the CI. It builds the kernel (without overwriting your existing Kconfig), recompiles the
bpf selftests, runs them (by default ``tools/testing/selftests/bpf/test_progs``) and
saves the resulting output (by default in ``~/.bpf_selftests``).

For more information on about using the script, run:

.. code-block:: console

  $ tools/testing/selftests/bpf/vmtest.sh -h

.. note:: The script uses pahole and clang based on host environment setting.
          If you want to change pahole and llvm, you can change `PATH` environment
          variable in the beginning of script.

.. note:: The script currently only supports x86_64.

Additional information about selftest failures are
documented here.

profiler[23] test failures with clang/llvm <12.0.0
==================================================

With clang/llvm <12.0.0, the profiler[23] test may fail.
The symptom looks like

.. code-block:: c

  // r9 is a pointer to map_value
  // r7 is a scalar
  17:       bf 96 00 00 00 00 00 00 r6 = r9
  18:       0f 76 00 00 00 00 00 00 r6 += r7
  math between map_value pointer and register with unbounded min value is not allowed

  // the instructions below will not be seen in the verifier log
  19:       a5 07 01 00 01 01 00 00 if r7 < 257 goto +1
  20:       bf 96 00 00 00 00 00 00 r6 = r9
  // r6 is used here

The verifier will reject such code with above error.
At insn 18 the r7 is indeed unbounded. The later insn 19 checks the bounds and
the insn 20 undoes map_value addition. It is currently impossible for the
verifier to understand such speculative pointer arithmetic.
Hence `this patch`__ addresses it on the compiler side. It was committed on llvm 12.

__ https://reviews.llvm.org/D85570

The corresponding C code

.. code-block:: c

  for (int i = 0; i < MAX_CGROUPS_PATH_DEPTH; i++) {
          filepart_length = bpf_probe_read_str(payload, ...);
          if (filepart_length <= MAX_PATH) {
                  barrier_var(filepart_length); // workaround
                  payload += filepart_length;
          }
  }

bpf_iter test failures with clang/llvm 10.0.0
=============================================

With clang/llvm 10.0.0, the following two bpf_iter tests failed:
  * ``bpf_iter/ipv6_route``
  * ``bpf_iter/netlink``

The symptom for ``bpf_iter/ipv6_route`` looks like

.. code-block:: c

  2: (79) r8 = *(u64 *)(r1 +8)
  ...
  14: (bf) r2 = r8
  15: (0f) r2 += r1
  ; BPF_SEQ_PRINTF(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen);
  16: (7b) *(u64 *)(r8 +64) = r2
  only read is supported

The symptom for ``bpf_iter/netlink`` looks like

.. code-block:: c

  ; struct netlink_sock *nlk = ctx->sk;
  2: (79) r7 = *(u64 *)(r1 +8)
  ...
  15: (bf) r2 = r7
  16: (0f) r2 += r1
  ; BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
  17: (7b) *(u64 *)(r7 +0) = r2
  only read is supported

This is due to a llvm BPF backend bug. `The fix`__
has been pushed to llvm 10.x release branch and will be
available in 10.0.1. The patch is available in llvm 11.0.0 trunk.

__  https://reviews.llvm.org/D78466

BPF CO-RE-based tests and Clang version
=======================================

A set of selftests use BPF target-specific built-ins, which might require
bleeding-edge Clang versions (Clang 12 nightly at this time).

Few sub-tests of core_reloc test suit (part of test_progs test runner) require
the following built-ins, listed with corresponding Clang diffs introducing
them to Clang/LLVM. These sub-tests are going to be skipped if Clang is too
old to support them, they shouldn't cause build failures or runtime test
failures:

- __builtin_btf_type_id() [0_, 1_, 2_];
- __builtin_preserve_type_info(), __builtin_preserve_enum_value() [3_, 4_].

.. _0: https://reviews.llvm.org/D74572
.. _1: https://reviews.llvm.org/D74668
.. _2: https://reviews.llvm.org/D85174
.. _3: https://reviews.llvm.org/D83878
.. _4: https://reviews.llvm.org/D83242