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Thu, 13 Apr 2023 08:49:25 -0700 (PDT) MIME-Version: 1.0 References: <40c60719-4bfe-b1a4-ead7-724b84637f55@web.de> <1a11455f-ab57-dce0-1677-6beb8492a257@web.de> <54a21fea-64e3-de67-82ef-d61b90ffad05@web.de> In-Reply-To: <54a21fea-64e3-de67-82ef-d61b90ffad05@web.de> From: Ian Rogers Date: Thu, 13 Apr 2023 08:49:14 -0700 Message-ID: Subject: Re: [PATCH] perf map: Delete two variable initialisations before null pointer checks in sort__sym_from_cmp() To: Markus Elfring Cc: kernel-janitors@vger.kernel.org, linux-perf-users@vger.kernel.org, Adrian Hunter , Alexander Shishkin , Andi Kleen , Arnaldo Carvalho de Melo , German Gomez , Ingo Molnar , Jiri Olsa , Kan Liang , Mark Rutland , Namhyung Kim , cocci@inria.fr, LKML Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On Thu, Apr 13, 2023 at 6:03=E2=80=AFAM Markus Elfring wrote: > > Date: Thu, 13 Apr 2023 14:46:39 +0200 > > Addresses of two data structure members were determined before > corresponding null pointer checks in the implementation of > the function =E2=80=9Csort__sym_from_cmp=E2=80=9D. > > Thus avoid the risk for undefined behaviour by removing extra > initialisations for the local variables =E2=80=9Cfrom_l=E2=80=9D and =E2= =80=9Cfrom_r=E2=80=9D > (also because they were already reassigned with the same value > behind this pointer check). > > This issue was detected by using the Coccinelle software. > > Fixes: 1b9e97a2a95e4941dcfa968c4b2e04022e9a343e ("perf tools: Fix report = -F symbol_from for data without branch info") > Signed-off-by: Markus Elfring Acked-by: Ian Rogers Thanks, Ian > --- > tools/perf/util/sort.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c > index 80c9960c37e5..f2ffaf90648e 100644 > --- a/tools/perf/util/sort.c > +++ b/tools/perf/util/sort.c > @@ -1020,8 +1020,7 @@ static int hist_entry__dso_to_filter(struct hist_en= try *he, int type, > static int64_t > sort__sym_from_cmp(struct hist_entry *left, struct hist_entry *right) > { > - struct addr_map_symbol *from_l =3D &left->branch_info->from; > - struct addr_map_symbol *from_r =3D &right->branch_info->from; > + struct addr_map_symbol *from_l, *from_r; > > if (!left->branch_info || !right->branch_info) > return cmp_null(left->branch_info, right->branch_info); > -- > 2.40.0 >