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[24.205.208.113]) by smtp.gmail.com with ESMTPSA id z15-20020a05622a060f00b002e2070bf899sm3079882qta.90.2022.03.19.18.51.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Mar 2022 18:51:49 -0700 (PDT) From: trix@redhat.com To: jpoimboe@redhat.com, jikos@kernel.org, mbenes@suse.cz, pmladek@suse.com, joe.lawrence@redhat.com, nathan@kernel.org, ndesaulniers@google.com Cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Tom Rix Subject: [PATCH v2] livepatch: Reorder to use before freeing a pointer Date: Sat, 19 Mar 2022 18:51:43 -0700 Message-Id: <20220320015143.2208591-1-trix@redhat.com> X-Mailer: git-send-email 2.26.3 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Tom Rix Clang static analysis reports this issue livepatch-shadow-fix1.c:113:2: warning: Use of memory after it is freed pr_info("%s: dummy @ %p, prevented leak @ %p\n", ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The pointer is freed in the previous statement. Reorder the pr_info to report before the free. Similar issue in livepatch-shadow-fix2.c Signed-off-by: Tom Rix Acked-by: David Vernet Acked-by: Joe Lawrence Reviewed-by: Petr Mladek --- v2: Fix similar issue in livepatch-shadow-fix2.c samples/livepatch/livepatch-shadow-fix1.c | 2 +- samples/livepatch/livepatch-shadow-fix2.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/samples/livepatch/livepatch-shadow-fix1.c b/samples/livepatch/= livepatch-shadow-fix1.c index 918ce17b43fda..6701641bf12d4 100644 --- a/samples/livepatch/livepatch-shadow-fix1.c +++ b/samples/livepatch/livepatch-shadow-fix1.c @@ -109,9 +109,9 @@ static void livepatch_fix1_dummy_leak_dtor(void *obj, v= oid *shadow_data) void *d =3D obj; int **shadow_leak =3D shadow_data; =20 - kfree(*shadow_leak); pr_info("%s: dummy @ %p, prevented leak @ %p\n", __func__, d, *shadow_leak); + kfree(*shadow_leak); } =20 static void livepatch_fix1_dummy_free(struct dummy *d) diff --git a/samples/livepatch/livepatch-shadow-fix2.c b/samples/livepatch/= livepatch-shadow-fix2.c index 29fe5cd420472..361046a4f10cf 100644 --- a/samples/livepatch/livepatch-shadow-fix2.c +++ b/samples/livepatch/livepatch-shadow-fix2.c @@ -61,9 +61,9 @@ static void livepatch_fix2_dummy_leak_dtor(void *obj, voi= d *shadow_data) void *d =3D obj; int **shadow_leak =3D shadow_data; =20 - kfree(*shadow_leak); pr_info("%s: dummy @ %p, prevented leak @ %p\n", __func__, d, *shadow_leak); + kfree(*shadow_leak); } =20 static void livepatch_fix2_dummy_free(struct dummy *d) --=20 2.26.3