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=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 F3522C04AB4 for ; Thu, 16 May 2019 09:43:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5F4C2087E for ; Thu, 16 May 2019 09:43:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="URTlWqVu"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="Y/o7rx7d" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727263AbfEPJnK (ORCPT ); Thu, 16 May 2019 05:43:10 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:48582 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727080AbfEPJnK (ORCPT ); Thu, 16 May 2019 05:43:10 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 5A53460A43; Thu, 16 May 2019 09:43:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1557999789; bh=mAn2iFFHckRd3ohvLpQRx+OaGWXOZ6D8XXn0kPEekd8=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=URTlWqVuyLjs/kQDtcpdDUxVr8YgTjjgWYoj8xT4cmA+YBXjOTLUtXzxGUaIdvWxy YARC98uXjl/3+M1c2whPrpKePPUyHhxJQl39pdr9G0WA+eRLAObMHpQbYp913pAa/+ E6bcqevL/ax8GRHYdIxPgI0BvX7ulmevPuC1rqoI= Received: from [10.204.79.15] (blr-c-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: mojha@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 93AFB60A42; Thu, 16 May 2019 09:43:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1557999788; bh=mAn2iFFHckRd3ohvLpQRx+OaGWXOZ6D8XXn0kPEekd8=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=Y/o7rx7dOzVIjuyKGUaoCLvWiuZ4NBsagvC0uwH4r990f8hlxKDrH8MawVLp6Lcyo bQz1teq5l7EAwZ8+NpnOJ1CxToyk16Gb15cawjBs1lRnZ9PxEULx0B/CnVKtpEc3yw ze6oC17PBVWw2wsSRcN2eAxvQMOlaW3JJfb5zgtA= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 93AFB60A42 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=mojha@codeaurora.org Subject: Re: [PATCH] spi: bitbang: Fix NULL pointer dereference in spi_unregister_master To: YueHaibing , broonie@kernel.org, axel.lin@ingics.com Cc: linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, albeu@free.fr, lorenzo.bianconi@redhat.com References: <20190516075656.25880-1-yuehaibing@huawei.com> From: Mukesh Ojha Message-ID: Date: Thu, 16 May 2019 15:13:03 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190516075656.25880-1-yuehaibing@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/16/2019 1:26 PM, YueHaibing wrote: > If spi_register_master fails in spi_bitbang_start > because device_add failure, We should return the > error code other than 0, otherwise calling > spi_bitbang_stop may trigger NULL pointer dereference > like this: > > BUG: KASAN: null-ptr-deref in __list_del_entry_valid+0x45/0xd0 > Read of size 8 at addr 0000000000000000 by task syz-executor.0/3661 > > CPU: 0 PID: 3661 Comm: syz-executor.0 Not tainted 5.1.0+ #28 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 > Call Trace: > dump_stack+0xa9/0x10e > ? __list_del_entry_valid+0x45/0xd0 > ? __list_del_entry_valid+0x45/0xd0 > __kasan_report+0x171/0x18d > ? __list_del_entry_valid+0x45/0xd0 > kasan_report+0xe/0x20 > __list_del_entry_valid+0x45/0xd0 > spi_unregister_controller+0x99/0x1b0 > spi_lm70llp_attach+0x3ae/0x4b0 [spi_lm70llp] > ? 0xffffffffc1128000 > ? klist_next+0x131/0x1e0 > ? driver_detach+0x40/0x40 [parport] > port_check+0x3b/0x50 [parport] > bus_for_each_dev+0x115/0x180 > ? subsys_dev_iter_exit+0x20/0x20 > __parport_register_driver+0x1f0/0x210 [parport] > ? 0xffffffffc1150000 > do_one_initcall+0xb9/0x3b5 > ? perf_trace_initcall_level+0x270/0x270 > ? kasan_unpoison_shadow+0x30/0x40 > ? kasan_unpoison_shadow+0x30/0x40 > do_init_module+0xe0/0x330 > load_module+0x38eb/0x4270 > ? module_frob_arch_sections+0x20/0x20 > ? kernel_read_file+0x188/0x3f0 > ? find_held_lock+0x6d/0xd0 > ? fput_many+0x1a/0xe0 > ? __do_sys_finit_module+0x162/0x190 > __do_sys_finit_module+0x162/0x190 > ? __ia32_sys_init_module+0x40/0x40 > ? __mutex_unlock_slowpath+0xb4/0x3f0 > ? wait_for_completion+0x240/0x240 > ? vfs_write+0x160/0x2a0 > ? lockdep_hardirqs_off+0xb5/0x100 > ? mark_held_locks+0x1a/0x90 > ? do_syscall_64+0x14/0x2a0 > do_syscall_64+0x72/0x2a0 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Reported-by: Hulk Robot > Fixes: 702a4879ec33 ("spi: bitbang: Let spi_bitbang_start() take a reference to master") > Signed-off-by: YueHaibing Reviewed-by: Mukesh Ojha Cheers, -Mukesh > --- > drivers/spi/spi-bitbang.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c > index dd9a8c54..be95be4 100644 > --- a/drivers/spi/spi-bitbang.c > +++ b/drivers/spi/spi-bitbang.c > @@ -403,7 +403,7 @@ int spi_bitbang_start(struct spi_bitbang *bitbang) > if (ret) > spi_master_put(master); > > - return 0; > + return ret; > } > EXPORT_SYMBOL_GPL(spi_bitbang_start); >