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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 D471AECDE47 for ; Thu, 8 Nov 2018 22:03:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8EE4D208A3 for ; Thu, 8 Nov 2018 22:03:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Vg4/UkPk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8EE4D208A3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729894AbeKIHk6 (ORCPT ); Fri, 9 Nov 2018 02:40:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:60862 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727514AbeKIHk6 (ORCPT ); Fri, 9 Nov 2018 02:40:58 -0500 Received: from localhost (unknown [208.72.13.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9765B2081C; Thu, 8 Nov 2018 22:03:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541714608; bh=KF1+SMMpaPgtXyqm8gCUM7YzS+VrUMvFDzDc3ijra4I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vg4/UkPkVQAHurECDpYfCU9UHO0Z7iLZBVGrWW57NUstOnbi7vZ3ohFTffHMFyJwl YzAHL4mwv0tn73UwXVeQy3NLKffPPZ2/jB9836tlr4AqmEz521aJp8gtJbPUA48vS4 428W6EkbGyhdkVrzCYElZvsr3RKJdvNSygbAqslo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Robinson , Stefan Wahren , =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= , Wolfram Sang , Sasha Levin Subject: [PATCH 4.9 041/171] i2c: bcm2835: Avoid possible NULL ptr dereference Date: Thu, 8 Nov 2018 13:50:11 -0800 Message-Id: <20181108215130.468707918@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181108215127.257643509@linuxfoundation.org> References: <20181108215127.257643509@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit ababb08938df7ac245d30a58b95b94ecf8dc04fc ] Since commit e2474541032d ("bcm2835: Fix hang for writing messages larger than 16 bytes") the interrupt handler is prone to a possible NULL pointer dereference. This could happen if an interrupt fires before curr_msg is set by bcm2835_i2c_xfer_msg() and randomly occurs on the RPi 3. Even this is an unexpected behavior the driver must handle that with an error instead of a crash. Reported-by: Peter Robinson Fixes: e2474541032d ("bcm2835: Fix hang for writing messages larger than 16 bytes") Signed-off-by: Stefan Wahren Acked-by: Noralf Trønnes Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-bcm2835.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c index f283b714aa79..7ed09865cb4b 100644 --- a/drivers/i2c/busses/i2c-bcm2835.c +++ b/drivers/i2c/busses/i2c-bcm2835.c @@ -128,7 +128,9 @@ static irqreturn_t bcm2835_i2c_isr(int this_irq, void *data) } if (val & BCM2835_I2C_S_DONE) { - if (i2c_dev->curr_msg->flags & I2C_M_RD) { + if (!i2c_dev->curr_msg) { + dev_err(i2c_dev->dev, "Got unexpected interrupt (from firmware?)\n"); + } else if (i2c_dev->curr_msg->flags & I2C_M_RD) { bcm2835_drain_rxfifo(i2c_dev); val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S); } -- 2.17.1