linux.git/tools/testing/selftests/bpf/test_loader.c, branch v6.17

selftests/bpf: Allow macros in __retval

2025-06-26T16:44:46+00:00

Allow macro expansion for values passed to the `__retval` and
`__retval_unpriv` attributes. This is especially useful for testing
programs which return various error codes.

With this change, the code for parsing special literals can be made
simpler, as the literals are defined via macros. The only exception is
INT_MIN which expands to (-INT_MAX -1), which is not single number and
cannot be parsed by strtol. So, we instead use a prefixed literal
_INT_MIN in __retval and handle it separately (assign the expected
return to INT_MIN). Also, strtol cannot handle the "ll" suffix so change
the value of POINTER_VALUE from 0xcafe4all to 0xbadcafe.

Signed-off-by: Viktor Malik 
Link: https://lore.kernel.org/r/a6c6b551ae0575351faa7b7a1df52f9341a5cbe8.1750917800.git.vmalik@redhat.com
Signed-off-by: Alexei Starovoitov

selftests/bpf: Fix RELEASE build failure with gcc14

2025-06-17T17:18:30+00:00

With gcc14, when building with RELEASE=1, I hit four below compilation
failure:

Error 1:
  In file included from test_loader.c:6:
  test_loader.c: In function ‘run_subtest’: test_progs.h:194:17:
      error: ‘retval’ may be used uninitialized in this function
   [-Werror=maybe-uninitialized]
    194 |                 fprintf(stdout, ##format);           \
        |                 ^~~~~~~
  test_loader.c:958:13: note: ‘retval’ was declared here
    958 |         int retval, err, i;
        |             ^~~~~~

  The uninitialized var 'retval' actually could cause incorrect result.

Error 2:
  In function ‘test_fd_array_cnt’:
  prog_tests/fd_array.c:71:14: error: ‘btf_id’ may be used uninitialized in this
      function [-Werror=maybe-uninitialized]
     71 |         fd = bpf_btf_get_fd_by_id(id);
        |              ^~~~~~~~~~~~~~~~~~~~~~~~
  prog_tests/fd_array.c:302:15: note: ‘btf_id’ was declared here
    302 |         __u32 btf_id;
        |               ^~~~~~

  Changing ASSERT_GE to ASSERT_EQ can fix the compilation error. Otherwise,
  there is no functionality change.

Error 3:
  prog_tests/tailcalls.c: In function ‘test_tailcall_hierarchy_count’:
  prog_tests/tailcalls.c:1402:23: error: ‘fentry_data_fd’ may be used uninitialized
      in this function [-Werror=maybe-uninitialized]
     1402 |                 err = bpf_map_lookup_elem(fentry_data_fd, &i, &val);
          |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  The code is correct. The change intends to silence gcc errors.

Error 4: (this error only happens on arm64)
  In file included from prog_tests/log_buf.c:4:
  prog_tests/log_buf.c: In function ‘bpf_prog_load_log_buf’:
  ./test_progs.h:390:22: error: ‘log_buf’ may be used uninitialized [-Werror=maybe-uninitialized]
    390 |         int ___err = libbpf_get_error(___res);             \
        |                      ^~~~~~~~~~~~~~~~~~~~~~~~
  prog_tests/log_buf.c:158:14: note: in expansion of macro ‘ASSERT_OK_PTR’
    158 |         if (!ASSERT_OK_PTR(log_buf, "log_buf_alloc"))
        |              ^~~~~~~~~~~~~
  In file included from selftests/bpf/tools/include/bpf/bpf.h:32,
                 from ./test_progs.h:36:
  selftests/bpf/tools/include/bpf/libbpf_legacy.h:113:17:
    note: by argument 1 of type ‘const void *’ to ‘libbpf_get_error’ declared here
    113 | LIBBPF_API long libbpf_get_error(const void *ptr);
        |                 ^~~~~~~~~~~~~~~~

  Adding a pragma to disable maybe-uninitialized fixed the issue.

Signed-off-by: Yonghong Song 
Link: https://lore.kernel.org/r/20250617044956.2686668-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov

selftests/bpf: Fix caps for __xlated/jited_unpriv

2025-05-09T18:29:11+00:00

Currently, __xlated_unpriv and __jited_unpriv do not work because the
BPF syscall will overwrite info.jited_prog_len and info.xlated_prog_len
with 0 if the process is not bpf_capable(). This bug was not noticed
before, because there is no test that actually uses
__xlated_unpriv/__jited_unpriv.

To resolve this, simply restore the capabilities earlier (but still
after loading the program). Adding this here unconditionally is fine
because the function first checks that the capabilities were initialized
before attempting to restore them.

This will be important later when we add tests that check whether a
speculation barrier was inserted in the correct location.

Signed-off-by: Luis Gerhorst 
Fixes: 9c9f73391310 ("selftests/bpf: allow checking xlated programs in verifier_* tests")
Fixes: 7d743e4c759c ("selftests/bpf: __jited test tag to check disassembly after jit")
Acked-by: Kumar Kartikeya Dwivedi 
Tested-by: Eduard Zingerman 
Link: https://lore.kernel.org/r/20250501073603.1402960-2-luis.gerhorst@fau.de
Signed-off-by: Alexei Starovoitov

selftests/bpf: Fix cap_enable_effective() return code

2025-03-15T18:48:57+00:00

The caller of cap_enable_effective() expects negative error code.
Fix it.

Before:
  failed to restore CAP_SYS_ADMIN: -1, Unknown error -1

After:
  failed to restore CAP_SYS_ADMIN: -3, No such process
  failed to restore CAP_SYS_ADMIN: -22, Invalid argument

Signed-off-by: Feng Yang 
Acked-by: Eduard Zingerman 
Link: https://lore.kernel.org/r/20250305022234.44932-1-yangfeng59949@163.com
Signed-off-by: Alexei Starovoitov

selftests/bpf: Introduce __load_if_JITed annotation for tests

2025-02-15T03:55:15+00:00

In some cases, the verification logic under the interpreter and JIT
differs, such as may_goto, and the test program behaves differently under
different runtime modes, requiring separate verification logic for each
result.

Introduce __load_if_JITed and __load_if_no_JITed annotation for tests.

Signed-off-by: Jiayuan Chen 
Link: https://lore.kernel.org/r/20250214091823.46042-3-mrpre@163.com
Signed-off-by: Alexei Starovoitov

selftests/bpf: Introduce __caps_unpriv annotation for tests

2024-12-04T17:19:50+00:00

Add a __caps_unpriv annotation so that tests requiring specific
capabilities while dropping the rest can conveniently specify them
during selftest declaration instead of munging with capabilities at
runtime from the testing binary.

While at it, let us convert test_verifier_mtu to use this new support
instead.

Since we do not want to include linux/capability.h, we only defined the
four main capabilities BPF subsystem deals with in bpf_misc.h for use in
tests. If the user passes a CAP_SYS_NICE or anything else that's not
defined in the header, capability parsing code will return a warning.

Also reject strtol returning 0. CAP_CHOWN = 0 but we'll never need to
use it, and strtol doesn't errno on failed conversion. Fail the test in
such a case.

The original diff for this idea is available at link [0].

  [0]: https://lore.kernel.org/bpf/a1e48f5d9ae133e19adc6adf27e19d585e06bab4.camel@gmail.com

Signed-off-by: Eduard Zingerman 
[ Kartikeya: rebase on bpf-next, add warn to parse_caps, convert test_verifier_mtu ]
Signed-off-by: Kumar Kartikeya Dwivedi 
Link: https://lore.kernel.org/r/20241204044757.1483141-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov

selftests/bpf: attach struct_ops maps before test prog runs

2024-08-30T01:15:45+00:00

In test_loader based tests to bpf_map__attach_struct_ops()
before call to bpf_prog_test_run_opts() in order to trigger
bpf_struct_ops->reg() callbacks on kernel side.
This allows to use __retval macro for struct_ops tests.

Signed-off-by: Eduard Zingerman 
Signed-off-by: Martin KaFai Lau 
Link: https://lore.kernel.org/r/20240829210833.388152-6-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov

selftests/bpf: test_loader.c:get_current_arch() should not return 0

2024-08-23T14:29:02+00:00

At the moment, when test_loader.c:get_current_arch() can't determine
the arch, it returns 0. The arch check in run_subtest() looks as
follows:

	if ((get_current_arch() & spec->arch_mask) == 0) {
		test__skip();
		return;
	}

Which means that all test_loader based tests would be skipped if arch
could not be determined. get_current_arch() recognizes x86_64, arm64
and riscv64. Which means that CI skips test_loader tests for s390.

Fix this by making sure that get_current_arch() always returns
non-zero value. In combination with default spec->arch_mask == -1 this
should cover all possibilities.

Fixes: f406026fefa7 ("selftests/bpf: by default use arch mask allowing all archs")
Fixes: 7d743e4c759c ("selftests/bpf: __jited test tag to check disassembly after jit")
Signed-off-by: Eduard Zingerman 
Link: https://lore.kernel.org/r/20240823080644.263943-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov

selftests/bpf: by default use arch mask allowing all archs

2024-08-22T15:35:21+00:00

If test case does not specify architecture via __arch_* macro consider
that it should be run for all architectures.

Fixes: 7d743e4c759c ("selftests/bpf: __jited test tag to check disassembly after jit")
Signed-off-by: Eduard Zingerman 
Link: https://lore.kernel.org/r/20240822084112.3257995-6-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov

selftests/bpf: validate xlated same way as jited

2024-08-21T18:03:01+00:00

Both __xlated and __jited work with disassembly.
It is logical to have both work in a similar manner.

This commit updates __xlated macro handling in test_loader.c by making
it expect matches on sequential lines, same way as __jited operates.
For example:

    __xlated("1: *(u64 *)(r10 -16) = r1")      ;; matched on line N
    __xlated("3: r0 = &(void __percpu *)(r0)") ;; matched on line N+1

Also:

    __xlated("1: *(u64 *)(r10 -16) = r1")      ;; matched on line N
    __xlated("...")                            ;; not matched
    __xlated("3: r0 = &(void __percpu *)(r0)") ;; mantched on any
                                               ;; line >= N

Signed-off-by: Eduard Zingerman 
Link: https://lore.kernel.org/r/20240820102357.3372779-10-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov