kernel/tools/testing/selftests/bpf/trace_helpers.c, branch linux-6.2.y

selftests/bpf: Add load_kallsyms_refresh function

2022-10-25T17:14:51Z

Adding load_kallsyms_refresh function to re-read symbols from /proc/kallsyms file. This will be needed to get proper functions addresses from bpf_testmod.ko module, which is loaded/unloaded several times during the tests run, so symbols might be already old when we need to use them. Acked-by: Song Liu Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20221025134148.3300700-6-jolsa@kernel.org Signed-off-by: Alexei Starovoitov

selftests/bpf: Fix file descriptor leak in load_kallsyms()

2022-04-05T23:49:32Z

Currently, if sym_cnt > 0, it just returns and does not close file, fix it. Signed-off-by: Yuntao Wang Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220405145711.49543-1-ytcoode@gmail.com

selftests/bpf: Add kprobe_multi attach test

2022-03-18T03:17:19Z

Adding kprobe_multi attach test that uses new fprobe interface to attach kprobe program to multiple functions. The test is attaching programs to bpf_fentry_test* functions and uses single trampoline program bpf_prog_test_run to trigger bpf_fentry_test* functions. Signed-off-by: Jiri Olsa Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20220316122419.933957-11-jolsa@kernel.org

selftests/bpf: fix a clang compilation error

2022-01-27T17:48:49Z

When building selftests/bpf with clang make -j LLVM=1 make -C tools/testing/selftests/bpf -j LLVM=1 I hit the following compilation error: trace_helpers.c:152:9: error: variable 'found' is used uninitialized whenever 'while' loop exits because its condition is false [-Werror,-Wsometimes-uninitialized] while (fscanf(f, "%zx-%zx %s %zx %*[^\n]\n", &start, &end, buf, &base) == 4) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ trace_helpers.c:161:7: note: uninitialized use occurs here if (!found) ^~~~~ trace_helpers.c:152:9: note: remove the condition if it is always true while (fscanf(f, "%zx-%zx %s %zx %*[^\n]\n", &start, &end, buf, &base) == 4) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1 trace_helpers.c:145:12: note: initialize the variable 'found' to silence this warning bool found; ^ = false It is possible that for sane /proc/self/maps we may never hit the above issue in practice. But let us initialize variable 'found' properly to silence the compilation error. Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20220127163726.1442032-1-yhs@fb.com Signed-off-by: Alexei Starovoitov

selftests/bpf: fix uprobe offset calculation in selftests

2022-01-27T04:04:01Z

Fix how selftests determine relative offset of a function that is uprobed. Previously, there was an assumption that uprobed function is always in the first executable region, which is not always the case (libbpf CI hits this case now). So get_base_addr() approach in isolation doesn't work anymore. So teach get_uprobe_offset() to determine correct memory mapping and calculate uprobe offset correctly. While at it, I merged together two implementations of get_uprobe_offset() helper, moving powerpc64-specific logic inside (had to add extra {} block to avoid unused variable error for insn). Also ensured that uprobed functions are never inlined, but are still static (and thus local to each selftest), by using a no-op asm volatile block internally. I didn't want to keep them global __weak, because some tests use uprobe's ref counter offset (to test USDT-like logic) which is not compatible with non-refcounted uprobe. So it's nicer to have each test uprobe target local to the file and guaranteed to not be inlined or skipped by the compiler (which can happen with static functions, especially if compiling selftests with -O2). Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20220126193058.3390292-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov

selftests/bpf: Guess function end for test_get_branch_snapshot

2021-10-26T04:43:05Z

Function in modules could appear in /proc/kallsyms in random order. ffffffffa02608a0 t bpf_testmod_loop_test ffffffffa02600c0 t __traceiter_bpf_testmod_test_writable_bare ffffffffa0263b60 d __tracepoint_bpf_testmod_test_write_bare ffffffffa02608c0 T bpf_testmod_test_read ffffffffa0260d08 t __SCT__tp_func_bpf_testmod_test_writable_bare ffffffffa0263300 d __SCK__tp_func_bpf_testmod_test_read ffffffffa0260680 T bpf_testmod_test_write ffffffffa0260860 t bpf_testmod_test_mod_kfunc Therefore, we cannot reliably use kallsyms_find_next() to find the end of a function. Replace it with a simple guess (start + 128). This is good enough for this test. Signed-off-by: Song Liu Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211022234814.318457-1-songliubraving@fb.com

selftests/bpf: Add test for bpf_get_branch_snapshot

2021-09-13T17:53:50Z

This test uses bpf_get_branch_snapshot from a fexit program. The test uses a target function (bpf_testmod_loop_test) and compares the record against kallsyms. If there isn't enough record matching kallsyms, the test fails. Signed-off-by: Song Liu Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20210910183352.3151445-4-songliubraving@fb.com

selftests/bpf: Add ref_ctr_offset selftests

2021-08-16T22:45:08Z

Extend attach_probe selftests to specify ref_ctr_offset for uprobe/uretprobe and validate that its value is incremented from zero. Turns out that once uprobe is attached with ref_ctr_offset, uretprobe for the same location/function *has* to use ref_ctr_offset as well, otherwise perf_event_open() fails with -EINVAL. So this test uses ref_ctr_offset for both uprobe and uretprobe, even though for the purpose of test uprobe would be enough. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210815070609.987780-17-andrii@kernel.org

selftests/bpf: Extract uprobe-related helpers into trace_helpers.{c,h}

2021-08-16T22:45:08Z

Extract two helpers used for working with uprobes into trace_helpers.{c,h} to be re-used between multiple uprobe-using selftests. Also rename get_offset() into more appropriate get_uprobe_offset(). Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210815070609.987780-14-andrii@kernel.org

selftests/bpf: Ksyms_btf to test typed ksyms

2020-10-02T21:59:25Z

Selftests for typed ksyms. Tests two types of ksyms: one is a struct, the other is a plain int. This tests two paths in the kernel. Struct ksyms will be converted into PTR_TO_BTF_ID by the verifier while int typed ksyms will be converted into PTR_TO_MEM. Signed-off-by: Hao Luo Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200929235049.2533242-4-haoluo@google.com