perf dlfilter: Be defensive against potential NULL dereference

In the unlikely case of having a symbol without a mapping, avoid a
NULL dereference that clang-tidy warns about.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: llvm@lists.linux.dev
Cc: Ming Wang <wangming01@loongson.cn>
Cc: Tom Rix <trix@redhat.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20231009183920.200859-11-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

diff --git a/tools/perf/util/dlfilter.c b/tools/perf/util/dlfilter.c
index 1dbf27822ee28f385d4ba93a116eb3117e26cd43..5e54832137a99e842ff71a2ef881885671f1bb23 100644 (file)
--- a/tools/perf/util/dlfilter.c
+++ b/tools/perf/util/dlfilter.c
@@ -52,8 +52,10 @@ static void al_to_d_al(struct addr_location *al, struct perf_dlfilter_al *d_al)
                d_al->sym_end = sym->end;
                if (al->addr < sym->end)
                        d_al->symoff = al->addr - sym->start;
-               else
+               else if (al->map)
                        d_al->symoff = al->addr - map__start(al->map) - sym->start;
+               else
+                       d_al->symoff = 0;
                d_al->sym_binding = sym->binding;
        } else {
                d_al->sym = NULL;