linux-stable/tools/testing/selftests/bpf
Andrei Matei 7a22930c41 selftest/bpf: Verifier tests for var-off access
Add tests for the new functionality - reading and writing to the stack
through a variable-offset pointer.

Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210207011027.676572-4-andreimatei1@gmail.com
2021-02-10 10:44:19 -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 .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
prog_tests selftests/bpf: Add missing cleanup in atomic_bounds test 2021-02-08 17:55:01 -08:00
progs bpf/selftests: Update the IMA test to use BPF ring buffer 2021-02-04 16:35:05 -08:00
verifier selftest/bpf: Verifier tests for var-off access 2021-02-10 10:44:19 -08:00
.gitignore bpf, selftests: Fold test_current_pid_tgid_new_ns into test_progs. 2021-01-20 14:10:35 -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 selftests/bpf: Add Userspace tests for TCP_WINDOW_CLAMP 2020-12-03 17:23:24 -08:00
bpf_util.h selftests: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
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 tools: Factor Clang, LLC and LLVM utils definitions 2021-01-29 01:25:34 +01:00
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 selftests/bpf: Add test for "bpftool feature" command 2020-02-26 18:34:34 +01:00
test_bpftool.sh selftests/bpf: Add test for "bpftool feature" command 2020-02-26 18:34:34 +01:00
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 selftests: Use consistent include paths for libbpf 2020-01-20 16:37:45 -08:00
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 selftests/bpf: Add test based on port range for BPF flow dissector 2020-01-27 11:25:07 +01:00
test_ftrace.sh selftests/bpf: Test function_graph tracer and bpf trampoline together 2019-12-11 15:19:29 -08:00
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_socket_cookie.c selftests/bpf: Don't use deprecated libbpf APIs 2020-09-03 17:14:40 -07:00
test_sockmap.c selftests/bpf: Fix invalid use of strncat in test_sockmap 2020-12-03 18:07:05 -08:00
test_stub.c selftests/bpf: Integrate verbose verifier log into test_progs 2019-11-24 16:58:45 -08:00
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 selftests, bpf: Fix test_tc_tunnel hanging 2019-11-18 21:31:49 +01:00
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: Add xdpdrv mode for test_xdp_redirect 2020-07-31 00:43:49 +02:00
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 selftests: bpf: correct perror strings 2019-11-28 22:40:30 -08:00
xdping.h
xdpxceiver.c selftests/bpf: Avoid useless void *-casts 2021-01-26 00:05:02 +01:00
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