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2022-07-19selftests/bpf: fix a test for snprintf() overflowDan Carpenter1-1/+1
The snprintf() function returns the number of bytes which *would* have been copied if there were space. In other words, it can be > sizeof(pin_path). Fixes: c0fa1b6c3efc ("bpf: btf: Add BTF tests") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/r/YtZ+aD/tZMkgOUw+@kili Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-28selftests/bpf: remove last tests with legacy BPF map definitionsAndrii Nakryiko1-1/+0
Libbpf 1.0 stops support legacy-style BPF map definitions. Selftests has been migrated away from using legacy BPF map definitions except for two selftests, to make sure that legacy functionality still worked in pre-1.0 libbpf. Now it's time to let those tests go as libbpf 1.0 is imminent. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220627211527.2245459-14-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-21selftests/bpf: allow BTF specs and func infos in test_verifier testsEduard Zingerman1-1/+0
The BTF and func_info specification for test_verifier tests follows the same notation as in prog_tests/btf.c tests. E.g.: ... .func_info = { { 0, 6 }, { 8, 7 } }, .func_info_cnt = 2, .btf_strings = "\0int\0", .btf_types = { BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), BTF_PTR_ENC(1), }, ... The BTF specification is loaded only when specified. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/r/20220620235344.569325-3-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07selftests/bpf: Test BTF_KIND_ENUM64 for deduplicationYonghong Song1-2/+95
Add a few unit tests for BTF_KIND_ENUM64 deduplication. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062713.3725409-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07selftests/bpf: Add BTF_KIND_ENUM64 unit testsYonghong Song1-0/+36
Add unit tests for basic BTF_KIND_ENUM64 encoding. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062708.3724845-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-07selftests/bpf: Fix selftests failureYonghong Song1-20/+0
The kflag is supported now for BTF_KIND_ENUM. So remove the test which tests verifier failure due to existence of kflag. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220607062657.3723737-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-04-20selftests/bpf: Add tests for type tag order validationKumar Kartikeya Dwivedi1-0/+99
Add a few test cases that ensure we catch cases of badly ordered type tags in modifier chains. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220419164608.1990559-3-memxor@gmail.com
2022-04-11selftests/bpf: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCKYafang Shao1-1/+0
We have switched to memcg-based memory accouting and thus the rlimit is not needed any more. LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK was introduced in libbpf for backward compatibility, so we can use it instead now. After this change, the header tools/testing/selftests/bpf/bpf_rlimit.h can be removed. This patch also removes the useless header sys/resource.h from many files in tools/testing/selftests/bpf/. Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220409125958.92629-3-laoar.shao@gmail.com
2022-02-15selftests/bpf: Fix GCC11 compiler warnings in -O2 modeAndrii Nakryiko1-1/+1
When compiling selftests in -O2 mode with GCC1, we get three new compilations warnings about potentially uninitialized variables. Compiler is wrong 2 out of 3 times, but this patch makes GCC11 happy anyways, as it doesn't cost us anything and makes optimized selftests build less annoying. The amazing one is tc_redirect case of token that is malloc()'ed before ASSERT_OK_PTR() check is done on it. Seems like GCC pessimistically assumes that libbpf_get_error() will dereference the contents of the pointer (no it won't), so the only way I found to shut GCC up was to do zero-initializaing calloc(). This one was new to me. For linfo case, GCC didn't realize that linfo_size will be initialized by the function that is returning linfo_size as out parameter. core_reloc.c case was a real bug, we can goto cleanup before initializing obj. But we don't need to do any clean up, so just continue iteration intstead. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20220211190927.1434329-1-andrii@kernel.org
2022-02-07selftests/bpf: Fix strict mode calculationMauricio Vásquez1-1/+1
"(__LIBBPF_STRICT_LAST - 1) & ~LIBBPF_STRICT_MAP_DEFINITIONS" is wrong as it is equal to 0 (LIBBPF_STRICT_NONE). Let's use "LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS" now that the previous commit makes it possible in libbpf. Fixes: 93b8952d223a ("libbpf: deprecate legacy BPF map definitions") Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220207145052.124421-4-mauricio@kinvolk.io
2022-02-04selftests/bpf: Add a selftest for invalid func btf with btf decl_tagYonghong Song1-0/+19
Added a selftest similar to [1] which exposed a kernel bug. Without the fix in the previous patch, the similar kasan error will appear. [1] https://lore.kernel.org/bpf/0000000000009b6eaa05d71a8c06@google.com/ Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20220203191732.742285-1-yhs@fb.com
2022-01-21libbpf: deprecate legacy BPF map definitionsAndrii Nakryiko1-0/+4
Enact deprecation of legacy BPF map definition in SEC("maps") ([0]). For the definitions themselves introduce LIBBPF_STRICT_MAP_DEFINITIONS flag for libbpf strict mode. If it is set, error out on any struct bpf_map_def-based map definition. If not set, libbpf will print out a warning for each legacy BPF map to raise awareness that it goes away. For any use of BPF_ANNOTATE_KV_PAIR() macro providing a legacy way to associate BTF key/value type information with legacy BPF map definition, warn through libbpf's pr_warn() error message (but don't fail BPF object open). BPF-side struct bpf_map_def is marked as deprecated. User-space struct bpf_map_def has to be used internally in libbpf, so it is left untouched. It should be enough for bpf_map__def() to be marked deprecated to raise awareness that it goes away. bpftool is an interesting case that utilizes libbpf to open BPF ELF object to generate skeleton. As such, even though bpftool itself uses full on strict libbpf mode (LIBBPF_STRICT_ALL), it has to relax it a bit for BPF map definition handling to minimize unnecessary disruptions. So opt-out of LIBBPF_STRICT_MAP_DEFINITIONS for bpftool. User's code that will later use generated skeleton will make its own decision whether to enforce LIBBPF_STRICT_MAP_DEFINITIONS or not. There are few tests in selftests/bpf that are consciously using legacy BPF map definitions to test libbpf functionality. For those, temporary opt out of LIBBPF_STRICT_MAP_DEFINITIONS mode for the duration of those tests. [0] Closes: https://github.com/libbpf/libbpf/issues/272 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220120060529.1890907-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2021-12-15selftests/bpf: Remove explicit setrlimit(RLIMIT_MEMLOCK) in main selftestsAndrii Nakryiko1-1/+0
As libbpf now is able to automatically take care of RLIMIT_MEMLOCK increase (or skip it altogether on recent enough kernels), remove explicit setrlimit() invocations in bench, test_maps, test_verifier, and test_progs. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211214195904.1785155-3-andrii@kernel.org
2021-12-11selftests/bpf: Replace all uses of bpf_load_btf() with bpf_btf_load()Andrii Nakryiko1-20/+30
Switch all selftests uses of to-be-deprecated bpf_load_btf() with equivalent bpf_btf_load() calls. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211209193840.1248570-10-andrii@kernel.org
2021-11-26selftests/bpf: Migrate selftests to bpf_map_create()Andrii Nakryiko1-33/+18
Conversion is straightforward for most cases. In few cases tests are using mutable map_flags and attribute structs, but bpf_map_create_opts can be used in the similar fashion, so there were no problems. Just lots of repetitive conversions. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211124193233.3115996-5-andrii@kernel.org
2021-11-16selftests/bpf: Add a dedup selftest with equivalent structure typesYonghong Song1-0/+26
Without previous libbpf patch, the following error will occur: $ ./test_progs -t btf ... do_test_dedup:FAIL:check btf_dedup failed errno:-22#13/205 btf/dedup: btf_type_tag #5, struct:FAIL And the previous libbpf patch fixed the issue. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211115163943.3922547-1-yhs@fb.com
2021-11-12selftests/bpf: Test BTF_KIND_DECL_TAG for deduplicationYonghong Song1-4/+135
Add BTF_KIND_TYPE_TAG duplication unit tests. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211112012635.1506853-1-yhs@fb.com
2021-11-12selftests/bpf: Add BTF_KIND_TYPE_TAG unit testsYonghong Song1-0/+18
Add BTF_KIND_TYPE_TAG unit tests. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211112012630.1506095-1-yhs@fb.com
2021-11-12libbpf: Turn btf_dedup_opts into OPTS-based structAndrii Nakryiko1-39/+7
btf__dedup() and struct btf_dedup_opts were added before we figured out OPTS mechanism. As such, btf_dedup_opts is non-extensible without breaking an ABI and potentially crashing user application. Unfortunately, btf__dedup() and btf_dedup_opts are short and succinct names that would be great to preserve and use going forward. So we use ___libbpf_override() macro approach, used previously for bpf_prog_load() API, to define a new btf__dedup() variant that accepts only struct btf * and struct btf_dedup_opts * arguments, and rename the old btf__dedup() implementation into btf__dedup_deprecated(). This keeps both source and binary compatibility with old and new applications. The biggest problem was struct btf_dedup_opts, which wasn't OPTS-based, and as such doesn't have `size_t sz;` as a first field. But btf__dedup() is a pretty rarely used API and I believe that the only currently known users (besides selftests) are libbpf's own bpf_linker and pahole. Neither use case actually uses options and just passes NULL. So instead of doing extra hacks, just rewrite struct btf_dedup_opts into OPTS-based one, move btf_ext argument into those opts (only bpf_linker needs to dedup btf_ext, so it's not a typical thing to specify), and drop never used `dont_resolve_fwds` option (it was never used anywhere, AFAIK, it makes BTF dedup much less useful and efficient). Just in case, for old implementation, btf__dedup_deprecated(), detect non-NULL options and error out with helpful message, to help users migrate, if there are any user playing with btf__dedup(). The last remaining piece is dedup_table_size, which is another anachronism from very early days of BTF dedup. Since then it has been reduced to the only valid value, 1, to request forced hash collisions. This is only used during testing. So instead introduce a bool flag to force collisions explicitly. This patch also adapts selftests to new btf__dedup() and btf_dedup_opts use to avoid selftests breakage. [0] Closes: https://github.com/libbpf/libbpf/issues/281 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111053624.190580-4-andrii@kernel.org
2021-11-07selftests/bpf: Free inner strings index in btf selftestAndrii Nakryiko1-4/+2
Inner array of allocated strings wasn't freed on success. Now it's always freed. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Hengqi Chen <hengqi.chen@gmail.com> Link: https://lore.kernel.org/bpf/20211107165521.9240-6-andrii@kernel.org
2021-10-23selftests/bpf: Test deduplication for BTF_KIND_DECL_TAG typedefYonghong Song1-6/+41
Add unit tests for deduplication of BTF_KIND_DECL_TAG to typedef types. Also changed a few comments from "tag" to "decl_tag" to match BTF_KIND_DECL_TAG enum value name. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211021195638.4019770-1-yhs@fb.com
2021-10-23selftests/bpf: Add BTF_KIND_DECL_TAG typedef unit testsYonghong Song1-0/+36
Test good and bad variants of typedef BTF_KIND_DECL_TAG encoding. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211021195633.4019472-1-yhs@fb.com
2021-10-23selftests/bpf: Switch to new btf__type_cnt/btf__raw_data APIsHengqi Chen1-5/+5
Replace the calls to btf__get_nr_types/btf__get_raw_data in selftests with new APIs btf__type_cnt/btf__raw_data. The old APIs will be deprecated in libbpf v0.7+. Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211022130623.1548429-6-hengqi.chen@gmail.com
2021-10-19bpf: Rename BTF_KIND_TAG to BTF_KIND_DECL_TAGYonghong Song1-80/+80
Patch set [1] introduced BTF_KIND_TAG to allow tagging declarations for struct/union, struct/union field, var, func and func arguments and these tags will be encoded into dwarf. They are also encoded to btf by llvm for the bpf target. After BTF_KIND_TAG is introduced, we intended to use it for kernel __user attributes. But kernel __user is actually a type attribute. Upstream and internal discussion showed it is not a good idea to mix declaration attribute and type attribute. So we proposed to introduce btf_type_tag as a type attribute and existing btf_tag renamed to btf_decl_tag ([2]). This patch renamed BTF_KIND_TAG to BTF_KIND_DECL_TAG and some other declarations with *_tag to *_decl_tag to make it clear the tag is for declaration. In the future, BTF_KIND_TYPE_TAG might be introduced per [3]. [1] https://lore.kernel.org/bpf/20210914223004.244411-1-yhs@fb.com/ [2] https://reviews.llvm.org/D111588 [3] https://reviews.llvm.org/D111199 Fixes: b5ea834dde6b ("bpf: Support for new btf kind BTF_KIND_TAG") Fixes: 5b84bd10363e ("libbpf: Add support for BTF_KIND_TAG") Fixes: 5c07f2fec003 ("bpftool: Add support for BTF_KIND_TAG") Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211012164838.3345699-1-yhs@fb.com
2021-10-06selftests/bpf: Switch to new bpf_object__next_{map,program} APIsHengqi Chen1-1/+1
Replace deprecated bpf_{map,program}__next APIs with newly added bpf_object__next_{map,program} APIs, so that no compilation warnings emit. Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20211003165844.4054931-3-hengqi.chen@gmail.com
2021-09-15selftests/bpf: Test BTF_KIND_TAG for deduplicationYonghong Song1-17/+175
Add unit tests for BTF_KIND_TAG deduplication for - struct and struct member - variable - func and func argument Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210914223052.248535-1-yhs@fb.com
2021-09-15selftests/bpf: Add BTF_KIND_TAG unit testsYonghong Song1-0/+245
Test good and bad variants of BTF_KIND_TAG encoding. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210914223047.248223-1-yhs@fb.com
2021-09-15selftests/bpf: Change NAME_NTH/IS_NAME_NTH for BTF_KIND_TAG formatYonghong Song1-2/+2
BTF_KIND_TAG ELF format has a component_idx which might have value -1. test_btf may confuse it with common_type.name as NAME_NTH checkes high 16bit to be 0xffff. Change NAME_NTH high 16bit check to be 0xfffe so it won't confuse with component_idx. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210914223041.248009-1-yhs@fb.com
2021-07-30tools: Replace btf__get_from_id() with btf__load_from_kernel_by_id()Quentin Monnet1-1/+2
Replace the calls to function btf__get_from_id(), which we plan to deprecate before the library reaches v1.0, with calls to btf__load_from_kernel_by_id() in tools/ (bpftool, perf, selftests). Update the surrounding code accordingly (instead of passing a pointer to the btf struct, get it as a return value from the function). Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210729162028.29512-6-quentin@isovalent.com
2021-07-30tools: Free BTF objects at various locationsQuentin Monnet1-0/+1
Make sure to call btf__free() (and not simply free(), which does not free all pointers stored in the struct) on pointers to struct btf objects retrieved at various locations. These were found while updating the calls to btf__get_from_id(). Fixes: 999d82cbc044 ("tools/bpf: enhance test_btf file testing to test func info") Fixes: 254471e57a86 ("tools/bpf: bpftool: add support for func types") Fixes: 7b612e291a5a ("perf tools: Synthesize PERF_RECORD_* for loaded BPF programs") Fixes: d56354dc4909 ("perf tools: Save bpf_prog_info and BTF of new BPF programs") Fixes: 47c09d6a9f67 ("bpftool: Introduce "prog profile" command") Fixes: fa853c4b839e ("perf stat: Enable counting events for BPF programs") Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210729162028.29512-5-quentin@isovalent.com
2021-05-26selftests/bpf: Turn on libbpf 1.0 mode and fix all IS_ERR checksAndrii Nakryiko1-46/+47
Turn ony libbpf 1.0 mode. Fix all the explicit IS_ERR checks that now will be broken because libbpf returns NULL on error (and sets errno). Fix ASSERT_OK_PTR and ASSERT_ERR_PTR to work for both old mode and new modes and use them throughout selftests. This is trivial to do by using libbpf_get_error() API that all libbpf users are supposed to use, instead of IS_ERR checks. A bunch of checks also did explicit -1 comparison for various fd-returning APIs. Such checks are replaced with >= 0 or < 0 cases. There were also few misuses of bpf_object__find_map_by_name() in test_maps. Those are fixed in this patch as well. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210525035935.1461796-3-andrii@kernel.org
2021-03-05selftests/bpf: Add BTF_KIND_FLOAT to the existing deduplication testsIlya Leoshkevich1-12/+31
Check that floats don't interfere with struct deduplication, that they are not merged with another kinds and that floats of different sizes are not merged with each other. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210226202256.116518-9-iii@linux.ibm.com
2021-03-05selftest/bpf: Add BTF_KIND_FLOAT testsIlya Leoshkevich1-0/+131
Test the good variants as well as the potential malformed ones. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210226202256.116518-8-iii@linux.ibm.com
2021-03-05selftests/bpf: Use the 25th bit in the "invalid BTF_INFO" testIlya Leoshkevich1-1/+1
The bit being checked by this test is no longer reserved after introducing BTF_KIND_FLOAT, so use the next one instead. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210226202256.116518-6-iii@linux.ibm.com
2021-01-22selftest/bpf: Fix typoJunlin Yang1-2/+2
Change 'exeeds' to 'exceeds'. Signed-off-by: Junlin Yang <yangjunlin@yulong.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210121122309.1501-1-angkery@163.com
2021-01-21bpf: Permit size-0 datasecYonghong Song1-0/+21
llvm patch https://reviews.llvm.org/D84002 permitted to emit empty rodata datasec if the elf .rodata section contains read-only data from local variables. These local variables will be not emitted as BTF_KIND_VARs since llvm converted these local variables as static variables with private linkage without debuginfo types. Such an empty rodata datasec will make skeleton code generation easy since for skeleton a rodata struct will be generated if there is a .rodata elf section. The existence of a rodata btf datasec is also consistent with the existence of a rodata map created by libbpf. The btf with such an empty rodata datasec will fail in the kernel though as kernel will reject a datasec with zero vlen and zero size. For example, for the below code, int sys_enter(void *ctx) { int fmt[6] = {1, 2, 3, 4, 5, 6}; int dst[6]; bpf_probe_read(dst, sizeof(dst), fmt); return 0; } We got the below btf (bpftool btf dump ./test.o): [1] PTR '(anon)' type_id=0 [2] FUNC_PROTO '(anon)' ret_type_id=3 vlen=1 'ctx' type_id=1 [3] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED [4] FUNC 'sys_enter' type_id=2 linkage=global [5] INT 'char' size=1 bits_offset=0 nr_bits=8 encoding=SIGNED [6] ARRAY '(anon)' type_id=5 index_type_id=7 nr_elems=4 [7] INT '__ARRAY_SIZE_TYPE__' size=4 bits_offset=0 nr_bits=32 encoding=(none) [8] VAR '_license' type_id=6, linkage=global-alloc [9] DATASEC '.rodata' size=0 vlen=0 [10] DATASEC 'license' size=0 vlen=1 type_id=8 offset=0 size=4 When loading the ./test.o to the kernel with bpftool, we see the following error: libbpf: Error loading BTF: Invalid argument(22) libbpf: magic: 0xeb9f ... [6] ARRAY (anon) type_id=5 index_type_id=7 nr_elems=4 [7] INT __ARRAY_SIZE_TYPE__ size=4 bits_offset=0 nr_bits=32 encoding=(none) [8] VAR _license type_id=6 linkage=1 [9] DATASEC .rodata size=24 vlen=0 vlen == 0 libbpf: Error loading .BTF into kernel: -22. BTF is optional, ignoring. Basically, libbpf changed .rodata datasec size to 24 since elf .rodata section size is 24. The kernel then rejected the BTF since vlen = 0. Note that the above kernel verifier failure can be worked around with changing local variable "fmt" to a static or global, optionally const, variable. This patch permits a datasec with vlen = 0 in kernel. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210119153519.3901963-1-yhs@fb.com
2020-11-06selftest/bpf: Relax btf_dedup test checksAndrii Nakryiko1-15/+25
Remove the requirement of a strictly exact string section contents. This used to be true when string deduplication was done through sorting, but with string dedup done through hash table, it's no longer true. So relax test harness to relax strings checks and, consequently, type checks, which now don't have to have exactly the same string offsets. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20201105043402.2530976-3-andrii@kernel.org
2020-09-16selftests/bpf: Merge most of test_btf into test_progsAndrii Nakryiko1-0/+6811
Merge 183 tests from test_btf into test_progs framework to be exercised regularly. All the test_btf tests that were moved are modeled as proper sub-tests in test_progs framework for ease of debugging and reporting. No functional or behavioral changes were intended, I tried to preserve original behavior as much as possible. E.g., `test_progs -v` will activate "always_log" flag to emit BTF validation log. The only difference is in reducing the max_entries limit for pretty-printing tests from (128 * 1024) to just 128 to reduce tests running time without reducing the coverage. Example test run: $ sudo ./test_progs -n 8 ... #8 btf:OK Summary: 1/183 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200916004819.3767489-1-andriin@fb.com