From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD971161 for ; Sat, 19 Mar 2022 16:52:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647708729; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=saWneBVb3Kut4BG7sQxMXnQsPh0IPbc8oGB5dOPI5bM=; b=bR3hCRhxp6/3SI8tY+7hTEkrehJe7bG2dNYv3OtqK7Lk+NZIMFxz2zEphQVxVxDbqUIs27 JAM4dXHV6p7caR2/Px/65dy3C5uo0OG24FXt2fAx5NjqmhLMG20Vuo7X+rkaCgq3ijftbe zeXQFMVTO/oGjSIF8bWSnRIf4WbNkQo= Received: from mail-qt1-f198.google.com (mail-qt1-f198.google.com [209.85.160.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-230-C8ResmatMuOwMjccjddHtA-1; Sat, 19 Mar 2022 12:52:08 -0400 X-MC-Unique: C8ResmatMuOwMjccjddHtA-1 Received: by mail-qt1-f198.google.com with SMTP id y23-20020ac85257000000b002e06697f2ebso7453307qtn.16 for ; Sat, 19 Mar 2022 09:52:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=saWneBVb3Kut4BG7sQxMXnQsPh0IPbc8oGB5dOPI5bM=; b=xp9787QO6kcAa6K9eePvh7OY5bjZwqoZGSQXgeygAvQ2IuU4pzDnkfqxIZpfC02RrS H8bz4a5Dg1XIys8f2shk0C5lhkhZkH76fr8j6ASIXlQOS6zKuUew9YhjvtBoBl3Uapmc ytc1E81KumaJr0E1Uop41z9ZETvcurexpi7iggWb+krTs9PvkxmcZ6qGM3xGSOIcChEf bpcM7T6REFd+ctFIuCkTo2OOsFJVgBBVdS2RclUAAIfNkymKcNqc3ZrA9wgsSWrXxtX4 dytFjm3maszDlARqirA+om9UbKX4b3mCcUdA61W811HEO22NFFDQ0QWaBFKakYfUQi6W uVcA== X-Gm-Message-State: AOAM531iiTePA3UPEPbXsP2Kd5CZm4YzYKrHtTghJORtu0n+tKMtRZVT sGqyyjR8m6QG4yyZuHiwGBrog7Gh19omKg29LVZMhDcsbWJZ0XSpyc+8H6F6Ga0ASn9oVJahA3u jJlPqzFs7L0cFRg== X-Received: by 2002:a05:6214:4103:b0:440:e4d1:a2a0 with SMTP id kc3-20020a056214410300b00440e4d1a2a0mr9740314qvb.42.1647708727835; Sat, 19 Mar 2022 09:52:07 -0700 (PDT) X-Google-Smtp-Source: ABdhPJw6jHqOfsabhjqcfSHg8Xl46akmD6Zgg5f+CqiERLbL97pJUpKF0JjaYcTkKZUJbiUaFmv2Ow== X-Received: by 2002:a05:6214:4103:b0:440:e4d1:a2a0 with SMTP id kc3-20020a056214410300b00440e4d1a2a0mr9740296qvb.42.1647708727655; Sat, 19 Mar 2022 09:52:07 -0700 (PDT) Received: from localhost.localdomain.com (024-205-208-113.res.spectrum.com. [24.205.208.113]) by smtp.gmail.com with ESMTPSA id t66-20020ae9df45000000b0064915aff85fsm5399938qkf.45.2022.03.19.09.52.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Mar 2022 09:52:07 -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] livepatch: Reorder to use before freeing a pointer Date: Sat, 19 Mar 2022 09:51:59 -0700 Message-Id: <20220319165159.2170650-1-trix@redhat.com> X-Mailer: git-send-email 2.26.3 Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=trix@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" 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. Signed-off-by: Tom Rix --- samples/livepatch/livepatch-shadow-fix1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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, void *shadow_data) void *d = obj; int **shadow_leak = shadow_data; - kfree(*shadow_leak); pr_info("%s: dummy @ %p, prevented leak @ %p\n", __func__, d, *shadow_leak); + kfree(*shadow_leak); } static void livepatch_fix1_dummy_free(struct dummy *d) -- 2.26.3