Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 24 Jul 2023 13:12:45 -0700
In-Reply-To: <20230724201247.748146-1-irogers@google.com>
Message-Id: <20230724201247.748146-3-irogers@google.com>
Mime-Version: 1.0
References: <20230724201247.748146-1-irogers@google.com>
Subject: [PATCH v1 2/4] perf parse-events: Avoid use uninitialized warning
From:   Ian Rogers <irogers@google.com>
To:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        Yang Jihong <yangjihong1@huawei.com>,
        Ravi Bangoria <ravi.bangoria@amd.com>,
        Carsten Haitzler <carsten.haitzler@arm.com>,
        Zhengjun Xing <zhengjun.xing@linux.intel.com>,
        James Clark <james.clark@arm.com>,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
        bpf@vger.kernel.org, llvm@lists.linux.dev
Cc:     maskray@google.com
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

With GCC LTO a potential use uninitialized is spotted:
```
In function =E2=80=98parse_events_config_bpf=E2=80=99,
    inlined from =E2=80=98parse_events_load_bpf=E2=80=99 at util/parse-even=
ts.c:874:8:
util/parse-events.c:792:37: error: =E2=80=98error_pos=E2=80=99 may be used =
uninitialized [-Werror=3Dmaybe-uninitialized]
  792 |                                 idx =3D term->err_term + error_pos;
      |                                     ^
util/parse-events.c: In function =E2=80=98parse_events_load_bpf=E2=80=99:
util/parse-events.c:765:13: note: =E2=80=98error_pos=E2=80=99 was declared =
here
  765 |         int error_pos;
      |             ^
```
So initialize at declaration.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/parse-events.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.=
c
index acde097e327c..da29061ecf49 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -762,7 +762,7 @@ parse_events_config_bpf(struct parse_events_state *pars=
e_state,
 			struct list_head *head_config)
 {
 	struct parse_events_term *term;
-	int error_pos;
+	int error_pos =3D 0;
=20
 	if (!head_config || list_empty(head_config))
 		return 0;
--=20
2.41.0.487.g6d72f3e995-goog