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From:   Ivan Babrou <ivan@cloudflare.com>
To:     linux-perf-users@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, kernel-team@cloudflare.com,
        Ivan Babrou <ivan@cloudflare.com>,
        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>,
        James Clark <james.clark@arm.com>,
        Ian Rogers <irogers@google.com>,
        Fangrui Song <maskray@google.com>
Subject: [PATCH] perf unwind: fix unitialized offset on aarch64
Date:   Fri,  1 Jul 2022 11:20:46 -0700
Message-Id: <20220701182046.12589-1-ivan@cloudflare.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Commit dc2cf4ca866f uncovered the following issue on aarch64:

    util/unwind-libunwind-local.c: In function 'find_proc_info':
    util/unwind-libunwind-local.c:386:28: error: 'offset' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    386 |                         if (ofs > 0) {
        |                            ^
    util/unwind-libunwind-local.c:199:22: note: 'offset' was declared here
    199 |         u64 address, offset;
        |                      ^~~~~~
    util/unwind-libunwind-local.c:371:20: error: 'offset' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    371 |                 if (ofs <= 0) {
        |                    ^
    util/unwind-libunwind-local.c:199:22: note: 'offset' was declared here
    199 |         u64 address, offset;
        |                      ^~~~~~
    util/unwind-libunwind-local.c:363:20: error: 'offset' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    363 |                 if (ofs <= 0) {
        |                    ^
    util/unwind-libunwind-local.c:199:22: note: 'offset' was declared here
    199 |         u64 address, offset;
        |                      ^~~~~~
    In file included from util/libunwind/arm64.c:37:

Signed-off-by: Ivan Babrou <ivan@cloudflare.com>
Fixes: dc2cf4ca866f
---
 tools/perf/util/unwind-libunwind-local.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
index 37622699c91a..eaa8fa4b34f3 100644
--- a/tools/perf/util/unwind-libunwind-local.c
+++ b/tools/perf/util/unwind-libunwind-local.c
@@ -197,7 +197,7 @@ static int elf_section_address_and_offset(int fd, const char *name, u64 *address
 #ifndef NO_LIBUNWIND_DEBUG_FRAME
 static u64 elf_section_offset(int fd, const char *name)
 {
-	u64 address, offset;
+	u64 address, offset = 0;
 
 	if (elf_section_address_and_offset(fd, name, &address, &offset))
 		return 0;
-- 
2.36.1