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| author | Andrii Nakryiko <andriin@fb.com> | 2019-07-23 14:11:33 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2019-07-23 15:59:12 -0700 |
| commit | f2a3e4e95f408314938d37fa3146a9f7b304ce74 (patch) | |
| tree | 2693646b1efb0420c38f07526bcef2c4e7d9ffb8 /tools/lib | |
| parent | 3e3bb69589e482e0783f28d4cd1d8e56fda0bcbb (diff) | |
| download | linux-f2a3e4e95f408314938d37fa3146a9f7b304ce74.tar.gz | |
libbpf: provide more helpful message on uninitialized global var
When BPF program defines uninitialized global variable, it's put into a special COMMON section. Libbpf will reject such programs, but will provide very unhelpful message with garbage-looking section index. This patch detects special section cases and gives more explicit error message. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/lib')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 794dd5064ae8..8741c39adb1c 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1760,15 +1760,22 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, (long long) sym.st_value, sym.st_name, name); shdr_idx = sym.st_shndx; + insn_idx = rel.r_offset / sizeof(struct bpf_insn); + pr_debug("relocation: insn_idx=%u, shdr_idx=%u\n", + insn_idx, shdr_idx); + + if (shdr_idx >= SHN_LORESERVE) { + pr_warning("relocation: not yet supported relo for non-static global \'%s\' variable in special section (0x%x) found in insns[%d].code 0x%x\n", + name, shdr_idx, insn_idx, + insns[insn_idx].code); + return -LIBBPF_ERRNO__RELOC; + } if (!bpf_object__relo_in_known_section(obj, shdr_idx)) { pr_warning("Program '%s' contains unrecognized relo data pointing to section %u\n", prog->section_name, shdr_idx); return -LIBBPF_ERRNO__RELOC; } - insn_idx = rel.r_offset / sizeof(struct bpf_insn); - pr_debug("relocation: insn_idx=%u\n", insn_idx); - if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) { if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) { pr_warning("incorrect bpf_call opcode\n"); |