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[2620:137:e000::1:20]) by mx.google.com with ESMTP id c1-20020a056402100100b00418c2b5bf7dsi24042517edu.607.2022.03.31.02.45.55; Thu, 31 Mar 2022 02:46:21 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b="c/a8HkvG"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233066AbiCaIkn (ORCPT + 99 others); Thu, 31 Mar 2022 04:40:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233057AbiCaIkh (ORCPT ); Thu, 31 Mar 2022 04:40:37 -0400 Received: from mail-ej1-x62c.google.com (mail-ej1-x62c.google.com [IPv6:2a00:1450:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9684D43483 for ; Thu, 31 Mar 2022 01:38:48 -0700 (PDT) Received: by mail-ej1-x62c.google.com with SMTP id qa43so46514902ejc.12 for ; Thu, 31 Mar 2022 01:38:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=9RMKKrryOVnu3VhzCD1VF7LZZR0DSgayzdUmb3Tu53k=; b=c/a8HkvGusD0VHfseWle6cB/KMsnNLxZtaI9E6YEPd2f3Ay7SSaywbcuyl/qOuXpx7 5/fkW2lXkltLFr3B0LVE0/SHh0jLHqaTBs5PWnEUBNmVxT18zw3pQfsa/HaoTRIAnmjs qPXoZCjSC7i04J1uDtkAmhsb4Vm0QdvIWMBQwPb2oJ6tzNUFdMucD/PFbUK7BFLZoGtq Xg7bHb/csIsmHtf35TzKjMp4iA6QDF+67WWet3t1AoXZsR4hzkkXATvSaSuFQWkmo9u/ 4QWXiMij+6bFeI32M7XMl93xmxqD+YufjQyzP79v6BNBoSAl+LidnUb/1nGSyma1IsOl VEvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=9RMKKrryOVnu3VhzCD1VF7LZZR0DSgayzdUmb3Tu53k=; b=b8Wq9A7TpDpCQrNyH99ysZbfkq1CqgFimpu75e0K+3fEQue4Fj+Fm7obOnzif8p4xp QRknDIu1TeK72GFfyKmE6Q47e9PG04Aiogb2hPszSOAXUhUoRhMY0A7g53xAsOSOIXU2 dh/y+gXUHC0fUvn0Vwqm6Dl4qeOuDY2m/8DLIaMgGEyxVwPLLRh1ErOcOJa8ijAqM//L Ir9WVAUa6CXejl1VKfaTJ7hvEtJTWn0mwh33kHOBlNw0j7wOu8M3JaNiLHJXQpRrbC9l 2dDSjV+NqRHLtkGIsaMZOK1Bnp32d+JMj1sr898ZN24cs2jpLZrF+Ro6U+XHeKaftXhR 6Erg== X-Gm-Message-State: AOAM5335yAB3n8iZUfgbr92x02e9r7fYZjBgdijzzigTDZlyJxAhgO+T V49GP7ozvUeJfZT2Dy+Jn4ffTWfXvmTHKYl5PlNsww== X-Received: by 2002:a17:906:5d06:b0:6df:b0ac:59c2 with SMTP id g6-20020a1709065d0600b006dfb0ac59c2mr4142364ejt.758.1648715926986; Thu, 31 Mar 2022 01:38:46 -0700 (PDT) MIME-Version: 1.0 References: <20220330211913.2068108-1-wonchung@google.com> In-Reply-To: From: Won Chung Date: Thu, 31 Mar 2022 01:38:34 -0700 Message-ID: Subject: Re: [PATCH v2] sound/hda: Add NULL check to component match callback function To: Takashi Iwai Cc: Jaroslav Kysela , Takashi Iwai , Heikki Krogerus , Mika Westerberg , Benson Leung , Prashant Malani , linux-kernel@vger.kernel.org, stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-17.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, ENV_AND_HDR_SPF_MATCH,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE,USER_IN_DEF_DKIM_WL,USER_IN_DEF_SPF_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 31, 2022 at 12:27 AM Takashi Iwai wrote: > > On Wed, 30 Mar 2022 23:19:13 +0200, > Won Chung wrote: > > > > Component match callback function needs to check if expected data is > > passed to it. Without this check, it can cause a NULL pointer > > dereference when another driver registers a component before i915 > > drivers have their component master fully bind. > > > > Fixes: 7b882fe3e3e8b ("ALSA: hda - handle multiple i915 device instances") > > Signed-off-by: Heikki Krogerus > > Signed-off-by: Mika Westerberg > > Signed-off-by: Won Chung > > --- > > - Add "Fixes" tag > > - Send to stable@vger.kernel.org > > You rather need to add "Cc: stable@vger.kernel.org" line to the patch > itself (around sign-off block), not actually Cc'ing the mail. > I edited manually, but please do it so at the next time. > > Although I applied the patch as-is now, I wonder... > > > > - if (!strcmp(dev->driver->name, "i915") && > > + if (dev->driver && !strcmp(dev->driver->name, "i915") && > > Can NULL dev->driver be really seen? I thought the components are > added by the drivers, hence they ought to have the driver field set. > But there can be corner cases I overlooked. > > > thanks, > > Takashi Hi Takashi, When I try using component_add in a different driver (usb4 in my case), I think dev->driver here is NULL because the i915 drivers do not have their component master fully bound when this new component is registered. When I test it, it seems to be causing a crash. Would it be okay for me to resend a new patch with the flags corrected? I have mistakenly added Heikki and Mika as "Signed-off-by" instead of "Suggested-by". I am sorry for that. Thanks, Won