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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 8EACCC43464 for ; Fri, 18 Sep 2020 02:50:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FEAC20771 for ; Fri, 18 Sep 2020 02:50:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600397440; bh=wsFsmx10K403yrxOZpompQPREIBq2xevZO+F+wIklwM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qoTvbsI5cdtbWPZrg7R9c7Y1jZhDk41iMPUhqYmQN58MeECpcM4GQB/yOqDrWDdCs /sonpVvL2p4dqH+6ygyxK/0AwdfJrZ6ro+DJGXHyTjdae/pfH5u2PCWRntBZ1p4JUA caEEpFbxLQ6nf3KXwIW0bfKZf0eQGns9MFNhs/58= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728124AbgIRCIk (ORCPT ); Thu, 17 Sep 2020 22:08:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:59932 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727460AbgIRCIc (ORCPT ); Thu, 17 Sep 2020 22:08:32 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9EA042395C; Fri, 18 Sep 2020 02:08:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600394908; bh=wsFsmx10K403yrxOZpompQPREIBq2xevZO+F+wIklwM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KqQsELIjfQTptGwRnWESTSnIiBON/GGbbAsae6bn94BBXfIwdTosLZR9nsUIHS6wN D13QvpgADDq/bG7GYetpXq1QDapGZoudk7lCuE5jr0zDPVuCGeavSE39djeVDaqqm+ sDJO/pC937jpDMf/lZZj6qpCbHi3DHR483vN7iAM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Lee Jones , Daniel Thompson , Mark Brown , Sasha Levin Subject: [PATCH AUTOSEL 4.19 021/206] mfd: mfd-core: Protect against NULL call-back function pointer Date: Thu, 17 Sep 2020 22:04:57 -0400 Message-Id: <20200918020802.2065198-21-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918020802.2065198-1-sashal@kernel.org> References: <20200918020802.2065198-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lee Jones [ Upstream commit b195e101580db390f50b0d587b7f66f241d2bc88 ] If a child device calls mfd_cell_{en,dis}able() without an appropriate call-back being set, we are likely to encounter a panic. Avoid this by adding suitable checking. Signed-off-by: Lee Jones Reviewed-by: Daniel Thompson Reviewed-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/mfd/mfd-core.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c index 182973df1aed4..77c965c6a65f1 100644 --- a/drivers/mfd/mfd-core.c +++ b/drivers/mfd/mfd-core.c @@ -32,6 +32,11 @@ int mfd_cell_enable(struct platform_device *pdev) const struct mfd_cell *cell = mfd_get_cell(pdev); int err = 0; + if (!cell->enable) { + dev_dbg(&pdev->dev, "No .enable() call-back registered\n"); + return 0; + } + /* only call enable hook if the cell wasn't previously enabled */ if (atomic_inc_return(cell->usage_count) == 1) err = cell->enable(pdev); @@ -49,6 +54,11 @@ int mfd_cell_disable(struct platform_device *pdev) const struct mfd_cell *cell = mfd_get_cell(pdev); int err = 0; + if (!cell->disable) { + dev_dbg(&pdev->dev, "No .disable() call-back registered\n"); + return 0; + } + /* only disable if no other clients are using it */ if (atomic_dec_return(cell->usage_count) == 0) err = cell->disable(pdev); -- 2.25.1