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 X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A4D79C433B4 for ; Thu, 29 Apr 2021 14:49:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7094C61447 for ; Thu, 29 Apr 2021 14:49:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240584AbhD2Otw (ORCPT ); Thu, 29 Apr 2021 10:49:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44846 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240633AbhD2Otq (ORCPT ); Thu, 29 Apr 2021 10:49:46 -0400 Received: from mail-wr1-x431.google.com (mail-wr1-x431.google.com [IPv6:2a00:1450:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 343B4C06138C for ; Thu, 29 Apr 2021 07:48:58 -0700 (PDT) Received: by mail-wr1-x431.google.com with SMTP id m9so54496377wrx.3 for ; Thu, 29 Apr 2021 07:48:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:in-reply-to:references:date:message-id :mime-version; bh=vngK38/uzYnT4W+jr6IRjRIJAM+iJCix31NgQ9EuLvg=; b=YTSzJGcJHQgMlVXHNlXeaegByzcdO/Ixq9cwa3gZIFs3WIVEICy7i6oaNv6IY9heK7 3c+2qFCcvore/t6PybqZ371mANjlIO6Gow70D+otyIZbAmzdIs25wLSskUQbnAeN6e/F Ka3IZAu9ACMS2YqTyCoGjzJdaTJLf6Bh5Q3u0ojWvmh3ox6/A/oHVkgYkmtR5Uk5ykVn 9MciTdw6XCQoZaeHTMxi/igOej912jK01qR+4ZtYYNTFHrluX9deMM+JEN8vmzveHWyr iUd6sEyPOAhufRaw9anUNU86N5EcjVMvyafncjUCAGlePRQXghhvzVcsKb39+t+pipJY iuwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=vngK38/uzYnT4W+jr6IRjRIJAM+iJCix31NgQ9EuLvg=; b=oDZ0aJD++drAMFutT8Iwk48RjRNMvtRibp6ueU5zROr4E2r5w7fN6el7mFlhOT6jeq kueh7ySPE76HGrxk9hSpeq2DU/o/qGsqyQeOSBgLWUCY3OQJmV/FA9ZEXnqPj3gX5Tk8 zmkB2y9mCXx0rKhNr0l1MigDSuVM/vcb47JDKIZvJe6g0LHFl7hbDpAT7cm3WexLsyOn y/dsUjmAC3I/6ygiKcO8riHN7CncZUkA66A74kPcUhoQEz0LzNDw32zHQnqDE+gvd+nI 9hsP4P123jw1lB/8VRI6z/b2ndtsSOL0mPtWc5MHBS/VuDqB2heGDLXXpRuDuA5FWPMv PFKA== X-Gm-Message-State: AOAM531T4k0zBVC/ywXEraWJjv8JMXMBUffo6LRJHE3oH/Vrl7TD6xp1 zQO2PAFmnKPgQWe+2+s5QMCoeQ== X-Google-Smtp-Source: ABdhPJzRr1ptHoMK+F/hhQ1TsfC2223uBRcGsPIsIY79GHjAwVNUN4USMf1S/BuOGfztjsVVwGhQrA== X-Received: by 2002:a5d:6da8:: with SMTP id u8mr218171wrs.48.1619707736884; Thu, 29 Apr 2021 07:48:56 -0700 (PDT) Received: from localhost ([2a01:cb19:826e:8e00:f37e:9091:b397:6f48]) by smtp.gmail.com with ESMTPSA id r2sm4995675wrt.79.2021.04.29.07.48.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Apr 2021 07:48:56 -0700 (PDT) From: Mattijs Korpershoek To: Dmitry Torokhov Cc: Matthias Brugger , fparent@baylibre.com, linux-input@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/7] Input: mtk-pmic-keys - check for NULL on of_match_device() In-Reply-To: <875z05y4a2.fsf@baylibre.com> References: <20210428164219.1115537-1-mkorpershoek@baylibre.com> <20210428164219.1115537-2-mkorpershoek@baylibre.com> <875z05y4a2.fsf@baylibre.com> Date: Thu, 29 Apr 2021 16:48:55 +0200 Message-ID: <87wnslw3hk.fsf@baylibre.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dmitry, Mattijs Korpershoek writes: > Hi Dmitry, > > Dmitry Torokhov writes: > >> Hi Mattijs, >> >> On Wed, Apr 28, 2021 at 06:42:13PM +0200, Mattijs Korpershoek wrote: >>> mtk-pmic-keys being a child device of mt6397, it will always get probed >>> when mt6397_probe() is called. >>> >>> This also happens when we have no device tree node matching >>> mediatek,mt6397-keys. >> >> It sounds for me that creating a platform device instance in case where >> we know need OF node, but do not have one, is wasteful. Can >> mt6397-core.c and/or MFD core be adjusted to not do that. > > You are right. Maybe I can fix MFD core instead. I will look into it. > > Thanks for your review. >> >>> >>> In that case, the mfd core warns us: >>> >>> [ 0.352175] mtk-pmic-keys: Failed to locate of_node [id: -1] >>> >>> Check return value from call to of_match_device() >>> in order to prevent a NULL pointer dereference. >>> >>> In case of NULL print error message and return -ENODEV >>> >>> Signed-off-by: Mattijs Korpershoek >>> --- >>> drivers/input/keyboard/mtk-pmic-keys.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/drivers/input/keyboard/mtk-pmic-keys.c b/drivers/input/keyboard/mtk-pmic-keys.c >>> index 62391d6c7da6..12c449eed026 100644 >>> --- a/drivers/input/keyboard/mtk-pmic-keys.c >>> +++ b/drivers/input/keyboard/mtk-pmic-keys.c >>> @@ -247,6 +247,9 @@ static int mtk_pmic_keys_probe(struct platform_device *pdev) >>> const struct of_device_id *of_id = >>> of_match_device(of_mtk_pmic_keys_match_tbl, &pdev->dev); >>> >>> + if (!of_id) >>> + return -ENODEV; >>> + >> >> So if we make MFD/6396 core smarter we would not be needing this. I >> guess there is still a possibility of someone stuffing "mtk-pmic-keys" >> into "driver_override" attribute of a random platform device but I >> wonder if we really need to take care of such scenarios... It turns out it was possible to make 6397-core smarter. I've submitted [1] to replace this patch. Thanks again for your suggestion. Please let me know if I should add your Suggested-by: in [1]. [1] https://patchwork.kernel.org/project/linux-mediatek/patch/20210429143811.2030717-1-mkorpershoek@baylibre.com/ instead >> >>> keys = devm_kzalloc(&pdev->dev, sizeof(*keys), GFP_KERNEL); >>> if (!keys) >>> return -ENOMEM; >>> -- >>> 2.27.0 >>> >> >> Thanks. >> >> -- >> Dmitry