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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 41631C43461 for ; Tue, 8 Sep 2020 11:27:42 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CC2A52087D for ; Tue, 8 Sep 2020 11:27:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="qK2KMGkc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CC2A52087D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:MIME-Version:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Owner; bh=pYtMpDVcHUw52QutQ7ySrO4stCKCPxBq/F6lIDZmFpI=; b=qK2KMGkcOZFvl5dv73b4PBBiCA 6i8VJL7YVfJs1BAplPyO3IvXeRwgE+efnNLCMxwuEN4LqdlfGaBljkKtotumHFBlm1u9nZvYshOWr xCMMU1vyvkmTdjMNPpnzWekDRcrAprGD7U34i7T8gw4aneD+9wUeYCawzocVu88YN8I9SQfT8E/Rd dpElHd27CAT2/f2lVFYVRBj/r0BthmQZSMl0S3JEpZpvY9kRUtDkaYY5FKrDfWZinRpT6ya7YadYj bnmjxd5g22G7Mg3Z/L9U9fDAT9dIG+PxY3DEOTCuf8/3XG4zU22Wt4lrKK+eNaSAnUyelieoQCXLt /wS5O2JA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFblZ-0003Nx-Hf; Tue, 08 Sep 2020 11:26:25 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFblV-0003Ms-Qd for linux-arm-kernel@lists.infradead.org; Tue, 08 Sep 2020 11:26:22 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D0EB631B; Tue, 8 Sep 2020 04:26:17 -0700 (PDT) Received: from usa.arm.com (e103737-lin.cambridge.arm.com [10.1.197.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 2B8123F66E; Tue, 8 Sep 2020 04:26:17 -0700 (PDT) From: Sudeep Holla To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] firmware: arm_scmi: Fix NULL pointer dereference in mailbox_chan_free Date: Tue, 8 Sep 2020 12:26:11 +0100 Message-Id: <20200908112611.31515-1-sudeep.holla@arm.com> X-Mailer: git-send-email 2.17.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200908_072621_935260_14E86EF6 X-CRM114-Status: GOOD ( 16.40 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Viresh Kumar , Cristian Marussi , Sudeep Holla MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org scmi_mailbox is obtained from cinfo->transport_info and the first call to mailbox_chan_free frees the channel and sets cinfo->transport_info to NULL. Care is taken to check for non NULL smbox->chan but smbox can itself be NULL. Fix it by checking for it without which, kernel crashes with below NULL pointer dereference and eventually kernel panic. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038 Modules linked in: scmi_module(-) Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Sep 2 2020 pstate: 80000005 (Nzcv daif -PAN -UAO BTYPE=--) pc : mailbox_chan_free+0x2c/0x70 [scmi_module] lr : idr_for_each+0x6c/0xf8 Call trace: mailbox_chan_free+0x2c/0x70 [scmi_module] idr_for_each+0x6c/0xf8 scmi_remove+0xa8/0xf0 [scmi_module] platform_drv_remove+0x34/0x58 device_release_driver_internal+0x118/0x1f0 driver_detach+0x58/0xe8 bus_remove_driver+0x64/0xe0 driver_unregister+0x38/0x68 platform_driver_unregister+0x1c/0x28 scmi_driver_exit+0x38/0x44 [scmi_module] ---[ end trace 17bde19f50436de9 ]--- Kernel panic - not syncing: Fatal exception SMP: stopping secondary CPUs Kernel Offset: 0x1d0000 from 0xffff800010000000 PHYS_OFFSET: 0x80000000 CPU features: 0x0240022,25806004 Memory Limit: none ---[ end Kernel panic - not syncing: Fatal exception ]--- Cc: Cristian Marussi Cc: Viresh Kumar Fixes: 5c8a47a5a91d ("firmware: arm_scmi: Make scmi core independent of the transport type") Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/mailbox.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/firmware/arm_scmi/mailbox.c b/drivers/firmware/arm_scmi/mailbox.c index cc2de207fe10..4626404be541 100644 --- a/drivers/firmware/arm_scmi/mailbox.c +++ b/drivers/firmware/arm_scmi/mailbox.c @@ -110,7 +110,7 @@ static int mailbox_chan_free(int id, void *p, void *data) struct scmi_chan_info *cinfo = p; struct scmi_mailbox *smbox = cinfo->transport_info; - if (!IS_ERR(smbox->chan)) { + if (smbox && !IS_ERR(smbox->chan)) { mbox_free_channel(smbox->chan); cinfo->transport_info = NULL; smbox->chan = NULL; -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel