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.gitignoreH A D03-Nov-2021617

bench.cH A D03-Nov-202113.4 KiB

bench.hH A D03-Nov-20211.8 KiB

benchs/H03-Nov-202112

bpf_legacy.hH A D06-Aug-2020781

bpf_rand.hH A D30-Jun-20183.1 KiB

bpf_rlimit.hH A D05-Apr-2018907

bpf_sockopt_helpers.hH A D21-Feb-2021457

bpf_tcp_helpers.hH A D01-Sep-20216.3 KiB

bpf_testmod/H03-Nov-20217

bpf_util.hH A D29-Jan-20201 KiB

btf_helpers.cH A D03-Nov-20216.2 KiB

btf_helpers.hH A D16-Dec-2020608

cgroup_helpers.cH A D03-Nov-202110.7 KiB

cgroup_helpers.hH A D03-Nov-2021793

configH A D30-Apr-2021981

flow_dissector_load.cH A D03-Nov-20212.4 KiB

flow_dissector_load.hH A D03-Nov-20211.3 KiB

get_cgroup_id_user.cH A D30-Apr-20213.7 KiB

gnu/H05-May-20173

ima_setup.shH A D16-Dec-20202.5 KiB

MakefileH A D19-Nov-202120.4 KiB

Makefile.docsH A D01-Jul-20212.2 KiB

map_tests/H30-Apr-20217

netcnt_common.hH A D01-Sep-2021910

network_helpers.cH A D17-Sep-20217.5 KiB

network_helpers.hH A D17-Sep-20211.6 KiB

prog_tests/H19-Nov-2021188

progs/H19-Nov-2021410

README.rstH A D03-Nov-20218.5 KiB

settingsH A D14-Aug-202010

test_bpftool.pyH A D03-Nov-20215.3 KiB

test_bpftool.shH A D01-Sep-2021415

test_bpftool_build.shH A D03-Nov-20213.9 KiB

test_bpftool_metadata.shH A D16-Oct-20201.6 KiB

test_bpftool_synctypes.pyH A D01-Sep-202120.1 KiB

test_btf.hH A D03-Nov-20212.5 KiB

test_cgroup_storage.cH A D21-Feb-20214.6 KiB

test_cpp.cppH A D29-Jan-2020572

test_dev_cgroup.cH A D06-Aug-20202 KiB

test_doc_build.shH A D01-Sep-2021638

test_flow_dissector.cH A D21-Feb-202118.2 KiB

test_flow_dissector.shH A D03-Nov-20215.1 KiB

test_ftrace.shH A D23-Dec-2019701

test_iptunnel_common.hH A D01-Jun-2019457

test_kmod.shH A D06-Aug-20201.3 KiB

test_lirc_mode2.shH A D28-Dec-2018736

test_lirc_mode2_user.cH A D28-Dec-20184.3 KiB

test_lpm_map.cH A D18-Jun-201922.9 KiB

test_lru_map.cH A D01-Jul-202123.6 KiB

test_lwt_ip_encap.shH A D17-Oct-202114.1 KiB

test_lwt_seg6local.shH A D06-Aug-20205.7 KiB

test_maps.cH A D01-Sep-202149.1 KiB

test_maps.hH A D08-May-2019350

test_offload.pyH A D23-Dec-202050.6 KiB

test_progs.cH A D03-Nov-202132.8 KiB

test_progs.hH A D03-Nov-20219.1 KiB

test_select_reuseport_common.hH A D30-Aug-2018587

test_skb_cgroup_id.shH A D02-Nov-20181.3 KiB

test_skb_cgroup_id_user.cH A D06-Aug-20203.5 KiB

test_sock.cH A D06-Aug-20209.1 KiB

test_sock_addr.cH A D21-Feb-202130.5 KiB

test_sock_addr.shH A D02-Nov-20181.1 KiB

test_sockmap.cH A D03-Nov-202144.3 KiB

test_stub.cH A D26-Nov-20191.3 KiB

test_sysctl.cH A D03-Nov-202140.2 KiB

test_tag.cH A D05-Apr-20184.2 KiB

test_tc_edt.shH A D02-Nov-20192.7 KiB

test_tc_tunnel.shH A D01-Sep-20217.5 KiB

test_tcp_check_syncookie.shH A D03-Nov-20211.7 KiB

test_tcp_check_syncookie_user.cH A D19-Sep-20194.8 KiB

test_tcp_hdr_options.hH A D16-Oct-20203.3 KiB

test_tcpbpf.hH A D16-Dec-2020434

test_tcpnotify.hH A D28-Dec-2018273

test_tcpnotify_user.cH A D01-Jul-20213.8 KiB

test_tunnel.shH A D03-Nov-202118.9 KiB

test_verifier.cH A D19-Nov-202136.5 KiB

test_verifier_log.cH A D05-Apr-20183.8 KiB

test_xdp_meta.shH A D03-Nov-20211.3 KiB

test_xdp_redirect.shH A D03-Nov-20211.7 KiB

test_xdp_redirect_multi.shH A D12-Nov-20216 KiB

test_xdp_veth.shH A D03-Nov-20213 KiB

test_xdp_vlan.shH A D03-Nov-20215.7 KiB

test_xdp_vlan_mode_generic.shH A D15-Aug-2019186

test_xdp_vlan_mode_native.shH A D15-Aug-2019180

test_xdping.shH A D12-Jul-20192 KiB

test_xsk.shH A D01-Sep-20214.3 KiB

testing_helpers.cH A D06-Aug-20201.5 KiB

testing_helpers.hH A D06-Aug-2020308

trace_helpers.cH A D03-Nov-20214.2 KiB

trace_helpers.hH A D01-Sep-2021564

urandom_read.cH A D08-May-2019552

verifier/H19-Nov-202191

vmtest.shH A D03-Nov-20219.4 KiB

with_addr.shH A D24-Oct-20181.3 KiB

with_tunnels.shH A D24-Oct-2018693

xdp_redirect_multi.cH A D12-Nov-20215.2 KiB

xdping.cH A D03-Nov-20215.8 KiB

xdping.hH A D12-Jul-2019283

xdpxceiver.cH A D03-Nov-202138.3 KiB

xdpxceiver.hH A D03-Nov-20213.4 KiB

xsk_prereqs.shH A D01-Sep-20211.8 KiB

README.rst

1==================
2BPF Selftest Notes
3==================
4General instructions on running selftests can be found in
5`Documentation/bpf/bpf_devel_QA.rst`__.
6
7__ /Documentation/bpf/bpf_devel_QA.rst#q-how-to-run-bpf-selftests
8
9=========================
10Running Selftests in a VM
11=========================
12
13It's now possible to run the selftests using ``tools/testing/selftests/bpf/vmtest.sh``.
14The script tries to ensure that the tests are run with the same environment as they
15would be run post-submit in the CI used by the Maintainers.
16
17This script downloads a suitable Kconfig and VM userspace image from the system used by
18the CI. It builds the kernel (without overwriting your existing Kconfig), recompiles the
19bpf selftests, runs them (by default ``tools/testing/selftests/bpf/test_progs``) and
20saves the resulting output (by default in ``~/.bpf_selftests``).
21
22Script dependencies:
23- clang (preferably built from sources, https://github.com/llvm/llvm-project);
24- pahole (preferably built from sources, https://git.kernel.org/pub/scm/devel/pahole/pahole.git/);
25- qemu;
26- docutils (for ``rst2man``);
27- libcap-devel.
28
29For more information on about using the script, run:
30
31.. code-block:: console
32
33  $ tools/testing/selftests/bpf/vmtest.sh -h
34
35.. note:: The script uses pahole and clang based on host environment setting.
36          If you want to change pahole and llvm, you can change `PATH` environment
37          variable in the beginning of script.
38
39.. note:: The script currently only supports x86_64.
40
41Additional information about selftest failures are
42documented here.
43
44profiler[23] test failures with clang/llvm <12.0.0
45==================================================
46
47With clang/llvm <12.0.0, the profiler[23] test may fail.
48The symptom looks like
49
50.. code-block:: c
51
52  // r9 is a pointer to map_value
53  // r7 is a scalar
54  17:       bf 96 00 00 00 00 00 00 r6 = r9
55  18:       0f 76 00 00 00 00 00 00 r6 += r7
56  math between map_value pointer and register with unbounded min value is not allowed
57
58  // the instructions below will not be seen in the verifier log
59  19:       a5 07 01 00 01 01 00 00 if r7 < 257 goto +1
60  20:       bf 96 00 00 00 00 00 00 r6 = r9
61  // r6 is used here
62
63The verifier will reject such code with above error.
64At insn 18 the r7 is indeed unbounded. The later insn 19 checks the bounds and
65the insn 20 undoes map_value addition. It is currently impossible for the
66verifier to understand such speculative pointer arithmetic.
67Hence `this patch`__ addresses it on the compiler side. It was committed on llvm 12.
68
69__ https://reviews.llvm.org/D85570
70
71The corresponding C code
72
73.. code-block:: c
74
75  for (int i = 0; i < MAX_CGROUPS_PATH_DEPTH; i++) {
76          filepart_length = bpf_probe_read_str(payload, ...);
77          if (filepart_length <= MAX_PATH) {
78                  barrier_var(filepart_length); // workaround
79                  payload += filepart_length;
80          }
81  }
82
83bpf_iter test failures with clang/llvm 10.0.0
84=============================================
85
86With clang/llvm 10.0.0, the following two bpf_iter tests failed:
87  * ``bpf_iter/ipv6_route``
88  * ``bpf_iter/netlink``
89
90The symptom for ``bpf_iter/ipv6_route`` looks like
91
92.. code-block:: c
93
94  2: (79) r8 = *(u64 *)(r1 +8)
95  ...
96  14: (bf) r2 = r8
97  15: (0f) r2 += r1
98  ; BPF_SEQ_PRINTF(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen);
99  16: (7b) *(u64 *)(r8 +64) = r2
100  only read is supported
101
102The symptom for ``bpf_iter/netlink`` looks like
103
104.. code-block:: c
105
106  ; struct netlink_sock *nlk = ctx->sk;
107  2: (79) r7 = *(u64 *)(r1 +8)
108  ...
109  15: (bf) r2 = r7
110  16: (0f) r2 += r1
111  ; BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
112  17: (7b) *(u64 *)(r7 +0) = r2
113  only read is supported
114
115This is due to a llvm BPF backend bug. `The fix`__
116has been pushed to llvm 10.x release branch and will be
117available in 10.0.1. The patch is available in llvm 11.0.0 trunk.
118
119__  https://reviews.llvm.org/D78466
120
121bpf_verif_scale/loop6.o test failure with Clang 12
122==================================================
123
124With Clang 12, the following bpf_verif_scale test failed:
125  * ``bpf_verif_scale/loop6.o``
126
127The verifier output looks like
128
129.. code-block:: c
130
131  R1 type=ctx expected=fp
132  The sequence of 8193 jumps is too complex.
133
134The reason is compiler generating the following code
135
136.. code-block:: c
137
138  ;       for (i = 0; (i < VIRTIO_MAX_SGS) && (i < num); i++) {
139      14:       16 05 40 00 00 00 00 00 if w5 == 0 goto +64 <LBB0_6>
140      15:       bc 51 00 00 00 00 00 00 w1 = w5
141      16:       04 01 00 00 ff ff ff ff w1 += -1
142      17:       67 05 00 00 20 00 00 00 r5 <<= 32
143      18:       77 05 00 00 20 00 00 00 r5 >>= 32
144      19:       a6 01 01 00 05 00 00 00 if w1 < 5 goto +1 <LBB0_4>
145      20:       b7 05 00 00 06 00 00 00 r5 = 6
146  00000000000000a8 <LBB0_4>:
147      21:       b7 02 00 00 00 00 00 00 r2 = 0
148      22:       b7 01 00 00 00 00 00 00 r1 = 0
149  ;       for (i = 0; (i < VIRTIO_MAX_SGS) && (i < num); i++) {
150      23:       7b 1a e0 ff 00 00 00 00 *(u64 *)(r10 - 32) = r1
151      24:       7b 5a c0 ff 00 00 00 00 *(u64 *)(r10 - 64) = r5
152
153Note that insn #15 has w1 = w5 and w1 is refined later but
154r5(w5) is eventually saved on stack at insn #24 for later use.
155This cause later verifier failure. The bug has been `fixed`__ in
156Clang 13.
157
158__  https://reviews.llvm.org/D97479
159
160BPF CO-RE-based tests and Clang version
161=======================================
162
163A set of selftests use BPF target-specific built-ins, which might require
164bleeding-edge Clang versions (Clang 12 nightly at this time).
165
166Few sub-tests of core_reloc test suit (part of test_progs test runner) require
167the following built-ins, listed with corresponding Clang diffs introducing
168them to Clang/LLVM. These sub-tests are going to be skipped if Clang is too
169old to support them, they shouldn't cause build failures or runtime test
170failures:
171
172- __builtin_btf_type_id() [0_, 1_, 2_];
173- __builtin_preserve_type_info(), __builtin_preserve_enum_value() [3_, 4_].
174
175.. _0: https://reviews.llvm.org/D74572
176.. _1: https://reviews.llvm.org/D74668
177.. _2: https://reviews.llvm.org/D85174
178.. _3: https://reviews.llvm.org/D83878
179.. _4: https://reviews.llvm.org/D83242
180
181Floating-point tests and Clang version
182======================================
183
184Certain selftests, e.g. core_reloc, require support for the floating-point
185types, which was introduced in `Clang 13`__. The older Clang versions will
186either crash when compiling these tests, or generate an incorrect BTF.
187
188__  https://reviews.llvm.org/D83289
189
190Kernel function call test and Clang version
191===========================================
192
193Some selftests (e.g. kfunc_call and bpf_tcp_ca) require a LLVM support
194to generate extern function in BTF.  It was introduced in `Clang 13`__.
195
196Without it, the error from compiling bpf selftests looks like:
197
198.. code-block:: console
199
200  libbpf: failed to find BTF for extern 'tcp_slow_start' [25] section: -2
201
202__ https://reviews.llvm.org/D93563
203
204btf_tag test and Clang version
205==============================
206
207The btf_tag selftest require LLVM support to recognize the btf_decl_tag attribute.
208It was introduced in `Clang 14`__.
209
210Without it, the btf_tag selftest will be skipped and you will observe:
211
212.. code-block:: console
213
214  #<test_num> btf_tag:SKIP
215
216__ https://reviews.llvm.org/D111588
217
218Clang dependencies for static linking tests
219===========================================
220
221linked_vars, linked_maps, and linked_funcs tests depend on `Clang fix`__ to
222generate valid BTF information for weak variables. Please make sure you use
223Clang that contains the fix.
224
225__ https://reviews.llvm.org/D100362
226
227Clang relocation changes
228========================
229
230Clang 13 patch `clang reloc patch`_  made some changes on relocations such
231that existing relocation types are broken into more types and
232each new type corresponds to only one way to resolve relocation.
233See `kernel llvm reloc`_ for more explanation and some examples.
234Using clang 13 to compile old libbpf which has static linker support,
235there will be a compilation failure::
236
237  libbpf: ELF relo #0 in section #6 has unexpected type 2 in .../bpf_tcp_nogpl.o
238
239Here, ``type 2`` refers to new relocation type ``R_BPF_64_ABS64``.
240To fix this issue, user newer libbpf.
241
242.. Links
243.. _clang reloc patch: https://reviews.llvm.org/D102712
244.. _kernel llvm reloc: /Documentation/bpf/llvm_reloc.rst
245
246Clang dependencies for the u32 spill test (xdpwall)
247===================================================
248The xdpwall selftest requires a change in `Clang 14`__.
249
250Without it, the xdpwall selftest will fail and the error message
251from running test_progs will look like:
252
253.. code-block:: console
254
255  test_xdpwall:FAIL:Does LLVM have https://reviews.llvm.org/D109073? unexpected error: -4007
256
257__ https://reviews.llvm.org/D109073
258