On 3/20/22 4:20 AM, Yonghong Song wrote:
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.
If we remove this one here in which locations is it missing then? Do these then
need an extra errno = -err statement before they goto err?
Cc: Delyan Kratunov <delyank@xxxxxx>
Fixes: 00389c58ffe9 ("00389c58ffe993782a8ba4bb5a34a102b1f6fe24")
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
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\
