From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6AFBC433EF for ; Tue, 9 Nov 2021 22:07:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A99DB61211 for ; Tue, 9 Nov 2021 22:07:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245172AbhKIWK0 (ORCPT ); Tue, 9 Nov 2021 17:10:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245214AbhKIWKX (ORCPT ); Tue, 9 Nov 2021 17:10:23 -0500 Received: from mail-pl1-x632.google.com (mail-pl1-x632.google.com [IPv6:2607:f8b0:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C551C061764 for ; Tue, 9 Nov 2021 14:07:37 -0800 (PST) Received: by mail-pl1-x632.google.com with SMTP id p18so1062730plf.13 for ; Tue, 09 Nov 2021 14:07:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=M2qdUNiBEBQDeK0BjbS3vsx6fFE75Q9hfv1+Lcc9xKI=; b=eKyfJx4ekZ7PKZ/Tla5faumT+492L4SC54+KYXAkhQAcdzW22mIf2s9kWFbED2yOj0 Kg5Cn5Fn01+GxO79KBfrOxbEAkoRJfB25dR2RHQD2qKWXZVBvLIY5wTW5YOxLb2cFyb4 /3ELMtkgqgdc1L6CD3Z+yKp94HSgFH5VwtJFzLHdG89v0qwISM3Nnc9LCqyeQ8/7r0vs JisKCKBVn/3bpn3bUpBZebr05rKiDooEYveat59RjfsiZTYW8IRSbHi4uB4DzoDOGBl+ ZLCoZuc+wgqwP6VG6jKGvKTT9Gacq6ZSejHgky3zeioEgoH1gjbre5c5eUga70/9z2wR zLhQ== 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=M2qdUNiBEBQDeK0BjbS3vsx6fFE75Q9hfv1+Lcc9xKI=; b=WO1SXzuiEBkrPe0198RTV1mU1jKEIeqCgnb438uylgUiqBjL8HzcLr61R0nujA8GZ1 AO1Z5pkfpejXBGthwJw2B8SQ51GrVX91/XDLoHvqTuWcFKgYPbTR12/xiPDi9FF/jv/5 mYO0WusSvJxt2Wor1Sxj1Q/bYoJTMy85aaIsOhH/Y4mvoRtW6g2xnfVhxdPqJoD+7f92 hRbaAI9JlBAsmx//0fDUd+y7YDzILcDRwlNn2kVyokc9pGpn+0tbfSuPCzkiJilsUNO5 9JRHuxPmgIF42ClW+NWlYPAlTUEPIC5Y3Ij2K2O9bICOoKalR+JQ4va+23OSkf9DnbGm gOkQ== X-Gm-Message-State: AOAM5305Vig7A3DDtSj8CrdEaqT5iwEH/lcah61e0MQK3x4afRQE00CP MFbxHC5iy0i9n7m8D4Wqz1mZDoYB+q0pMGiN X-Google-Smtp-Source: ABdhPJzgmkyJPbY+SnYexa4HTcdeCtfp+gbvf7WqTezcXpy3HRG4A9ofKpesggnd2wwr4fO2QHFdrg== X-Received: by 2002:a17:90a:4fa1:: with SMTP id q30mr11094832pjh.12.1636495656765; Tue, 09 Nov 2021 14:07:36 -0800 (PST) Received: from thinkpad.localdomain ([2804:14d:5c21:92d0:458e:ac7b:f0d6:7ef4]) by smtp.gmail.com with ESMTPSA id y130sm14494685pfg.202.2021.11.09.14.07.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Nov 2021 14:07:36 -0800 (PST) From: Luiz Sampaio To: ojeda@kernel.org Cc: linux-kernel@vger.kernel.org, Luiz Sampaio Subject: [PATCH v2 2/2] auxdisplay: charlcd: checking for pointer reference before dereferencing Date: Tue, 9 Nov 2021 19:07:32 -0300 Message-Id: <20211109220732.7973-3-sampaio.ime@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211109220732.7973-1-sampaio.ime@gmail.com> References: <20211109220732.7973-1-sampaio.ime@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Check if the pointer lcd->ops->init_display exists before dereferencing it. If a driver called charlcd_init() without defining the ops, this would return segmentation fault, as happened to me when implementing a charlcd driver. Checking the pointer before dereferencing protects from segmentation fault. Signed-off-by: Luiz Sampaio --- drivers/auxdisplay/charlcd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c index cca3b600c0ba..6d309e4971b6 100644 --- a/drivers/auxdisplay/charlcd.c +++ b/drivers/auxdisplay/charlcd.c @@ -578,6 +578,9 @@ static int charlcd_init(struct charlcd *lcd) * Since charlcd_init_display() needs to write data, we have to * enable mark the LCD initialized just before. */ + if (WARN_ON(!lcd->ops->init_display)) + return -EINVAL; + ret = lcd->ops->init_display(lcd); if (ret) return ret; -- 2.33.1