From d5adbdd77ecc1d841af244a10958792141830d30 Mon Sep 17 00:00:00 2001 From: Andrey Ignatov Date: Wed, 10 Apr 2019 18:36:43 -0700 Subject: [PATCH] libbpf: Fix build with gcc-8 Reported in [1]. With gcc 8.3.0 the following error is issued: cc -Ibpf@sta -I. -I.. -I.././include -I.././include/uapi -fdiagnostics-color=always -fsanitize=address,undefined -fno-omit-frame-pointer -pipe -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Werror -g -fPIC -g -O2 -Werror -Wall -Wno-pointer-arith -Wno-sign-compare -MD -MQ 'bpf@sta/src_libbpf.c.o' -MF 'bpf@sta/src_libbpf.c.o.d' -o 'bpf@sta/src_libbpf.c.o' -c ../src/libbpf.c ../src/libbpf.c: In function 'bpf_object__elf_collect': ../src/libbpf.c:947:18: error: 'map_def_sz' may be used uninitialized in this function [-Werror=maybe-uninitialized] if (map_def_sz <= sizeof(struct bpf_map_def)) { ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../src/libbpf.c:827:18: note: 'map_def_sz' was declared here int i, map_idx, map_def_sz, nr_syms, nr_maps = 0, nr_maps_glob = 0; ^~~~~~~~~~ According to [2] -Wmaybe-uninitialized is enabled by -Wall. Same error is generated by clang's -Wconditional-uninitialized. [1] https://github.com/libbpf/libbpf/pull/29#issuecomment-481902601 [2] https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html Fixes: d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections") Reported-by: Evgeny Vereshchagin Signed-off-by: Andrey Ignatov Acked-by: Yonghong Song Signed-off-by: Daniel Borkmann --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index e2a457e7c318..67484cf32b2e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -824,7 +824,7 @@ bpf_object__init_internal_map(struct bpf_object *obj, struct bpf_map *map, static int bpf_object__init_maps(struct bpf_object *obj, int flags) { - int i, map_idx, map_def_sz, nr_syms, nr_maps = 0, nr_maps_glob = 0; + int i, map_idx, map_def_sz = 0, nr_syms, nr_maps = 0, nr_maps_glob = 0; bool strict = !(flags & MAPS_RELAX_COMPAT); Elf_Data *symbols = obj->efile.symbols; Elf_Data *data = NULL; -- 2.30.2