From f97b8b9bd630fb76c0e9e11cbf390e3d64a144d7 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Sat, 19 Mar 2022 20:20:09 -0700 Subject: [PATCH] bpftool: Fix a bug in subskeleton code generation Compiled with clang by adding LLVM=1 both kernel and selftests/bpf build, I hit the following compilation error: In file included from /.../tools/testing/selftests/bpf/prog_tests/subskeleton.c:6: ./test_subskeleton_lib.subskel.h:168:6: error: variable 'err' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] if (!s->progs) ^~~~~~~~~ ./test_subskeleton_lib.subskel.h:181:11: note: uninitialized use occurs here errno = -err; ^~~ ./test_subskeleton_lib.subskel.h:168:2: note: remove the 'if' if its condition is always false if (!s->progs) ^~~~~~~~~~~~~~ The compilation error is triggered by the following code ... int err; obj = (struct test_subskeleton_lib *)calloc(1, sizeof(*obj)); if (!obj) { errno = ENOMEM; goto err; } ... err: test_subskeleton_lib__destroy(obj); errno = -err; ... in test_subskeleton_lib__open(). The 'err' is not initialized, yet it is used in 'errno = -err' later. The fix is to remove 'errno = -err' since errno has been set properly in all incoming branches. Fixes: 00389c58ffe9 ("bpftool: Add support for subskeletons") Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20220320032009.3106133-1-yhs@fb.com --- tools/bpf/bpftool/gen.c | 1 - 1 file changed, 1 deletion(-) diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 96bd2b33ccf6..7ba7ff55d2ea 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -1538,7 +1538,6 @@ static int do_subskeleton(int argc, char **argv) return obj; \n\ err: \n\ %1$s__destroy(obj); \n\ - errno = -err; \n\ return NULL; \n\ } \n\ \n\ -- 2.34.1