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| author | Andrii Nakryiko <andrii@kernel.org> | 2021-11-03 10:32:12 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2021-11-03 13:25:37 -0700 |
| commit | 0d6988e16a12ebd41d3e268992211b0ceba44ed7 (patch) | |
| tree | cbaba4bdd1ac6b5bd37756f205ac58b5eccf3280 /tools/lib/bpf/libbpf.c | |
| parent | 62554d52e71797eefa3fc15b54008038837bb2d4 (diff) | |
| download | lwn-0d6988e16a12ebd41d3e268992211b0ceba44ed7.tar.gz lwn-0d6988e16a12ebd41d3e268992211b0ceba44ed7.zip | |
libbpf: Fix section counting logic
e_shnum does include section #0 and as such is exactly the number of ELF
sections that we need to allocate memory for to use section indices as
array indices. Fix the off-by-one error.
This is purely accounting fix, previously we were overallocating one
too many array items. But no correctness errors otherwise.
Fixes: 25bbbd7a444b ("libbpf: Remove assumptions about uniqueness of .rodata/.data/.bss maps")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20211103173213.1376990-5-andrii@kernel.org
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0dc6465271ce..ecfea6c20042 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3190,11 +3190,11 @@ static int bpf_object__elf_collect(struct bpf_object *obj) Elf_Scn *scn; Elf64_Shdr *sh; - /* ELF section indices are 1-based, so allocate +1 element to keep - * indexing simple. Also include 0th invalid section into sec_cnt for - * simpler and more traditional iteration logic. + /* ELF section indices are 0-based, but sec #0 is special "invalid" + * section. e_shnum does include sec #0, so e_shnum is the necessary + * size of an array to keep all the sections. */ - obj->efile.sec_cnt = 1 + obj->efile.ehdr->e_shnum; + obj->efile.sec_cnt = obj->efile.ehdr->e_shnum; obj->efile.secs = calloc(obj->efile.sec_cnt, sizeof(*obj->efile.secs)); if (!obj->efile.secs) return -ENOMEM; |