From: Daniel Borkmann Date: Tue, 23 Apr 2019 22:45:57 +0000 (+0200) Subject: bpf, libbpf: fix segfault in bpf_object__init_maps' pr_debug statement X-Git-Tag: v5.4-rc1~1056^2~80^2~10^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4f8827d2b61ed32133e51f6a782bb69d80c7c3d4;p=platform%2Fkernel%2Flinux-rpi.git bpf, libbpf: fix segfault in bpf_object__init_maps' pr_debug statement Ran into it while testing; in bpf_object__init_maps() data can be NULL in the case where no map section is present. Therefore we simply cannot access data->d_size before NULL test. Move the pr_debug() where it's safe to access. Fixes: d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections") Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov --- diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 85315de..9052061 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -875,14 +875,14 @@ bpf_object__init_maps(struct bpf_object *obj, int flags) nr_maps++; } - /* Alloc obj->maps and fill nr_maps. */ - pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path, - nr_maps, data->d_size); if (!nr_maps && !nr_maps_glob) return 0; /* Assume equally sized map definitions */ if (data) { + pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path, + nr_maps, data->d_size); + map_def_sz = data->d_size / nr_maps; if (!data->d_size || (data->d_size % nr_maps) != 0) { pr_warning("unable to determine map definition size "