| Message ID | 20190411013643.2038247-1-rdna@fb.com |
|---|---|
| State | Accepted |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [bpf-next] libbpf: Fix build with gcc-8 | expand |
On 4/10/19 6:36 PM, Andrey Ignatov wrote: > 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 <evvers@ya.ru> > Signed-off-by: Andrey Ignatov <rdna@fb.com> Acked-by: Yonghong Song <yhs@fb.com> > --- > 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; >
On 04/11/2019 03:36 AM, Andrey Ignatov wrote: > 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 <evvers@ya.ru> > Signed-off-by: Andrey Ignatov <rdna@fb.com> Applied, thanks!
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;
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 <evvers@ya.ru> Signed-off-by: Andrey Ignatov <rdna@fb.com> --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)