From patchwork Tue Jun 23 19:58:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 223392 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_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 7C1DFC433E1 for ; Tue, 23 Jun 2020 20:45:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 59D172080C for ; Tue, 23 Jun 2020 20:45:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592945120; bh=o4PHRK78AEjEwD8SHYfozcVWsNFhfNTt6rbCYn+7N7Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PlMofk0vzC6MQ0jajL7Xn8gzYSKQT+COV45L/K35f7TATwTBck0eJfuRAVJPVjTa7 AQJIAGC4tQ5ZZw95e2ryWiOGhR8g2szI97NRi/JpdLT+OOSvufMUNYJRcCfLZ7cZIJ XH0B9fj4Bg3uwKWsNEvbyxF7NaVvUp3y+z6ijfVY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391667AbgFWUpS (ORCPT ); Tue, 23 Jun 2020 16:45:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:42690 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392628AbgFWUpQ (ORCPT ); Tue, 23 Jun 2020 16:45:16 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 AB37320656; Tue, 23 Jun 2020 20:45:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592945116; bh=o4PHRK78AEjEwD8SHYfozcVWsNFhfNTt6rbCYn+7N7Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PAoWmeFlvx7B5ON0neqA/qxrKcKSW8FmgwfmH1dKEzBMSBrmRHvoboLEbQjtOarl8 d5dwC1garln74OHjQQukZEk6GPNUTpOnzvvkqtKjHCczHBuUviAA/QXFj878Wu0Tw+ 3SuUQ/Mqt1Juz1rlDVE/IMoea7csVQhH03Km+RWk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kuppuswamy Sathyanarayanan , Sasha Levin Subject: [PATCH 4.14 046/136] drivers: base: Fix NULL pointer exception in __platform_driver_probe() if a driver developer is foolish Date: Tue, 23 Jun 2020 21:58:22 +0200 Message-Id: <20200623195305.957093812@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623195303.601828702@linuxfoundation.org> References: <20200623195303.601828702@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 bcb6519fe2113..0ee3cab88f70f 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -702,6 +702,8 @@ 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