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=-10.1 required=3.0 tests=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=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 DDB1BC433DF for ; Mon, 29 Jun 2020 20:30:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C13AB206A5 for ; Mon, 29 Jun 2020 20:30:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593462611; bh=ojkNZJqWMbc/F7lxRLH27wKd+z/RgEuxJow6+FmPxBY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=v/sVTiXTMn9bH+G0nY11Rmz+q2w3hJCRlb+R0jBXoZu+uHCatW6KdxCHggQtrS+vR 6asMC1h7EcOyGI5zuIAEFNMZbpZOIl+rSRXgTcx64Vfzfuqxhsv7dDbjq3FTwxQZbZ WZZiTHXLM1suuI5bq2fLBHAZLNMI3mGkunWfrgGw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389208AbgF2UaK (ORCPT ); Mon, 29 Jun 2020 16:30:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:37038 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732482AbgF2TZU (ORCPT ); Mon, 29 Jun 2020 15:25:20 -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 C100825382; Mon, 29 Jun 2020 15:40:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593445249; bh=ojkNZJqWMbc/F7lxRLH27wKd+z/RgEuxJow6+FmPxBY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GBmAVlFgzNuC6WdHIZ8I+/8S9YJq0Zrw46e+3cIg427WkZ5SCh9cIBs5JvimRN+/1 a1juNUISYmQ9T/3AjSxKQ7vt+qG94DP3eE+5hnVZJQR4LkkveUM8xZCBf955MPZ04S lPD2fEcqrouJ41gbi3ySmgf/lhPBcAhWZwtJ5sMg= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kuppuswamy Sathyanarayanan , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 4.9 032/191] drivers: base: Fix NULL pointer exception in __platform_driver_probe() if a driver developer is foolish Date: Mon, 29 Jun 2020 11:37:28 -0400 Message-Id: <20200629154007.2495120-33-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629154007.2495120-1-sashal@kernel.org> References: <20200629154007.2495120-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.229-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-4.9.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 4.9.229-rc1 X-KernelTest-Deadline: 2020-07-01T15:39+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kuppuswamy Sathyanarayanan [ Upstream commit 388bcc6ecc609fca1b4920de7dc3806c98ec535e ] If platform bus driver registration is failed then, accessing platform bus spin lock (&drv->driver.bus->p->klist_drivers.k_lock) in __platform_driver_probe() without verifying the return value __platform_driver_register() can lead to NULL pointer exception. So check the return value before attempting the spin lock. One such example is below: For a custom usecase, I have intentionally failed the platform bus registration and I expected all the platform device/driver registrations to fail gracefully. But I came across this panic issue. [ 1.331067] BUG: kernel NULL pointer dereference, address: 00000000000000c8 [ 1.331118] #PF: supervisor write access in kernel mode [ 1.331163] #PF: error_code(0x0002) - not-present page [ 1.331208] PGD 0 P4D 0 [ 1.331233] Oops: 0002 [#1] PREEMPT SMP [ 1.331268] CPU: 3 PID: 1 Comm: swapper/0 Tainted: G W 5.6.0-00049-g670d35fb0144 #165 [ 1.331341] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 [ 1.331406] RIP: 0010:_raw_spin_lock+0x15/0x30 [ 1.331588] RSP: 0000:ffffc9000001be70 EFLAGS: 00010246 [ 1.331632] RAX: 0000000000000000 RBX: 00000000000000c8 RCX: 0000000000000001 [ 1.331696] RDX: 0000000000000001 RSI: 0000000000000092 RDI: 0000000000000000 [ 1.331754] RBP: 00000000ffffffed R08: 0000000000000501 R09: 0000000000000001 [ 1.331817] R10: ffff88817abcc520 R11: 0000000000000670 R12: 00000000ffffffed [ 1.331881] R13: ffffffff82dbc268 R14: ffffffff832f070a R15: 0000000000000000 [ 1.331945] FS: 0000000000000000(0000) GS:ffff88817bd80000(0000) knlGS:0000000000000000 [ 1.332008] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.332062] CR2: 00000000000000c8 CR3: 000000000681e001 CR4: 00000000003606e0 [ 1.332126] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1.332189] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1.332252] Call Trace: [ 1.332281] __platform_driver_probe+0x92/0xee [ 1.332323] ? rtc_dev_init+0x2b/0x2b [ 1.332358] cmos_init+0x37/0x67 [ 1.332396] do_one_initcall+0x7d/0x168 [ 1.332428] kernel_init_freeable+0x16c/0x1c9 [ 1.332473] ? rest_init+0xc0/0xc0 [ 1.332508] kernel_init+0x5/0x100 [ 1.332543] ret_from_fork+0x1f/0x30 [ 1.332579] CR2: 00000000000000c8 [ 1.332616] ---[ end trace 3bd87f12e9010b87 ]--- [ 1.333549] note: swapper/0[1] exited with preempt_count 1 [ 1.333592] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 [ 1.333736] Kernel Offset: disabled Note, this can only be triggered if a driver errors out from this call, which should never happen. If it does, the driver needs to be fixed. Signed-off-by: Kuppuswamy Sathyanarayanan Link: https://lore.kernel.org/r/20200408214003.3356-1-sathyanarayanan.kuppuswamy@linux.intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/base/platform.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/base/platform.c b/drivers/base/platform.c index bef299ef62276..ec2e4b6bc56f5 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -692,6 +692,8 @@ int __init_or_module __platform_driver_probe(struct platform_driver *drv, /* temporary section violation during probe() */ drv->probe = probe; retval = code = __platform_driver_register(drv, module); + if (retval) + return retval; /* * Fixup that section violation, being paranoid about code scanning -- 2.25.1