linux-stable/tools/testing/selftests/bpf
Ciara Loftus d3e3bf5b4c selftests/bpf: Restructure xsk selftests
Prior to this commit individual xsk tests were launched from the
shell script 'test_xsk.sh'. When adding a new test type, two new test
configurations had to be added to this file - one for each of the
supported XDP 'modes' (skb or drv). Should zero copy support be added to
the xsk selftest framework in the future, three new test configurations
would need to be added for each new test type. Each new test type also
typically requires new CLI arguments for the xdpxceiver program.

This commit aims to reduce the overhead of adding new tests, by launching
the test configurations from within the xdpxceiver program itself, using
simple loops. Every test is run every time the C program is executed. Many
of the CLI arguments can be removed as a result.

Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/bpf/20210223162304.7450-4-ciara.loftus@intel.com
2021-02-26 12:08:48 -08:00
..
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 selftests/bpf: Test deadlock from recursive bpf_task_storage_[get|delete] 2021-02-26 11:51:48 -08:00
progs selftests/bpf: Test deadlock from recursive bpf_task_storage_[get|delete] 2021-02-26 11:51:48 -08:00
verifier selftests/bpf: Fix endianness issues in atomic tests 2021-02-10 11:55:22 -08:00
.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 selftests/bpf: Add benchmark runner infrastructure 2020-05-13 12:19:38 -07:00
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: Restructure xsk selftests 2021-02-26 12:08:48 -08:00
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: Restructure xsk selftests 2021-02-26 12:08:48 -08:00
xdpxceiver.h selftests/bpf: Restructure xsk selftests 2021-02-26 12:08:48 -08:00
xsk_prereqs.sh selftests/bpf: Restructure xsk selftests 2021-02-26 12:08:48 -08:00

==================
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