From 31ded1535e3182778a1d0e5c32711f55da3bc512 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Wed, 16 Feb 2022 16:01:00 -0300 Subject: [PATCH] perf bpf: Defer freeing string after possible strlen() on it This was detected by the gcc in Fedora Rawhide's gcc: 50 11.01 fedora:rawhide : FAIL gcc version 12.0.1 20220205 (Red Hat 12.0.1-0) (GCC) inlined from 'bpf__config_obj' at util/bpf-loader.c:1242:9: util/bpf-loader.c:1225:34: error: pointer 'map_opt' may be used after 'free' [-Werror=use-after-free] 1225 | *key_scan_pos += strlen(map_opt); | ^~~~~~~~~~~~~~~ util/bpf-loader.c:1223:9: note: call to 'free' here 1223 | free(map_name); | ^~~~~~~~~~~~~~ cc1: all warnings being treated as errors So do the calculations on the pointer before freeing it. Fixes: 04f9bf2bac72480c ("perf bpf-loader: Add missing '*' for key_scan_pos") Cc: Adrian Hunter Cc: Ian Rogers Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang ShaoBo Link: https://lore.kernel.org/lkml/Yg1VtQxKrPpS3uNA@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/bpf-loader.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 7ecfaac..16ec605 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -1220,9 +1220,10 @@ bpf__obj_config_map(struct bpf_object *obj, pr_debug("ERROR: Invalid map config option '%s'\n", map_opt); err = -BPF_LOADER_ERRNO__OBJCONF_MAP_OPT; out: - free(map_name); if (!err) *key_scan_pos += strlen(map_opt); + + free(map_name); return err; } -- 2.7.4