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=-7.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 C5016C433EC for ; Tue, 21 Jul 2020 10:48:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A4D172077D for ; Tue, 21 Jul 2020 10:48:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595328496; bh=mCVOD2/3rIZ2K7CMs4hFee4ep9/OgYgQYJgBZXG9RJc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=DUlP6W7oGDXls7uN+3h5u38PFJcj7fBYhUlVBCoOY90ANZ+Dfj80Stt9Zg1nIKNbZ qae8U2tp+tuukwdpHbzMwWR0+Bk15QsTTI4y0jzx0gceLE3hekJYxx9eP4VwWFmFgy mtbT2xStJFfzNPhnEDcZec9kwTk/tSgUpn4qUuNg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729207AbgGUKsM (ORCPT ); Tue, 21 Jul 2020 06:48:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:35190 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726089AbgGUKsM (ORCPT ); Tue, 21 Jul 2020 06:48:12 -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 C87AA20674; Tue, 21 Jul 2020 10:48:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595328491; bh=mCVOD2/3rIZ2K7CMs4hFee4ep9/OgYgQYJgBZXG9RJc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mW8j8WIQbBScJfrAarqnLyQlPtHFHdBRC0whN3aOU5rZVBRrHa5J6hxstqFFa5sFJ IUMzqgZ4LNvqcCyCQWgzosUiR9OrhGqczGLXzQxvT2Jz6RNhWeJ6IwyFsLEmpyQ4Eh LC++w/roMQVmC2ODhp4GomhzPJMIuDM6yArByN+c= Date: Tue, 21 Jul 2020 12:48:19 +0200 From: Greg KH To: Yang Yingliang Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, jslaby@suse.com Subject: Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx() Message-ID: <20200721104819.GA1678476@kroah.com> References: <20200721143852.4058352-1-yangyingliang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200721143852.4058352-1-yangyingliang@huawei.com> Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Tue, Jul 21, 2020 at 02:38:52PM +0000, Yang Yingliang wrote: > I got null-ptr-deref in serial8250_start_tx(): > > [ 78.114630] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 > [ 78.123778] Mem abort info: > [ 78.126560] ESR = 0x86000007 > [ 78.129603] EC = 0x21: IABT (current EL), IL = 32 bits > [ 78.134891] SET = 0, FnV = 0 > [ 78.137933] EA = 0, S1PTW = 0 > [ 78.141064] user pgtable: 64k pages, 48-bit VAs, pgdp=00000027d41a8600 > [ 78.147562] [0000000000000000] pgd=00000027893f0003, p4d=00000027893f0003, pud=00000027893f0003, pmd=00000027c9a20003, pte=0000000000000000 > [ 78.160029] Internal error: Oops: 86000007 [#1] SMP > [ 78.164886] Modules linked in: sunrpc vfat fat aes_ce_blk crypto_simd cryptd aes_ce_cipher crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce ses enclosure sg sbsa_gwdt ipmi_ssif spi_dw_mmio sch_fq_codel vhost_net tun vhost vhost_iotlb tap ip_tables ext4 mbcache jbd2 ahci hisi_sas_v3_hw libahci hisi_sas_main libsas hns3 scsi_transport_sas hclge libata megaraid_sas ipmi_si hnae3 ipmi_devintf ipmi_msghandler br_netfilter bridge stp llc nvme nvme_core xt_sctp sctp libcrc32c dm_mod nbd > [ 78.207383] CPU: 11 PID: 23258 Comm: null-ptr Not tainted 5.8.0-rc6+ #48 > [ 78.214056] Hardware name: Huawei TaiShan 2280 V2/BC82AMDC, BIOS 2280-V2 CS V3.B210.01 03/12/2020 > [ 78.222888] pstate: 80400089 (Nzcv daIf +PAN -UAO BTYPE=--) > [ 78.228435] pc : 0x0 > [ 78.230618] lr : serial8250_start_tx+0x160/0x260 > [ 78.235215] sp : ffff800062eefb80 > [ 78.238517] x29: ffff800062eefb80 x28: 0000000000000fff > [ 78.243807] x27: ffff800062eefd80 x26: ffff202fd83b3000 > [ 78.249098] x25: ffff800062eefd80 x24: ffff202fd83b3000 > [ 78.254388] x23: ffff002fc5e50be8 x22: 0000000000000002 > [ 78.259679] x21: 0000000000000001 x20: 0000000000000000 > [ 78.264969] x19: ffffa688827eecc8 x18: 0000000000000000 > [ 78.270259] x17: 0000000000000000 x16: 0000000000000000 > [ 78.275550] x15: ffffa68881bc67a8 x14: 00000000000002e6 > [ 78.280841] x13: ffffa68881bc67a8 x12: 000000000000c539 > [ 78.286131] x11: d37a6f4de9bd37a7 x10: ffffa68881cccff0 > [ 78.291421] x9 : ffffa68881bc6000 x8 : ffffa688819daa88 > [ 78.296711] x7 : ffffa688822a0f20 x6 : ffffa688819e0000 > [ 78.302002] x5 : ffff800062eef9d0 x4 : ffffa68881e707a8 > [ 78.307292] x3 : 0000000000000000 x2 : 0000000000000002 > [ 78.312582] x1 : 0000000000000001 x0 : ffffa688827eecc8 > [ 78.317873] Call trace: > [ 78.320312] 0x0 > [ 78.322147] __uart_start.isra.9+0x64/0x78 > [ 78.326229] uart_start+0xb8/0x1c8 > [ 78.329620] uart_flush_chars+0x24/0x30 > [ 78.333442] n_tty_receive_buf_common+0x7b0/0xc30 > [ 78.338128] n_tty_receive_buf+0x44/0x2c8 > [ 78.342122] tty_ioctl+0x348/0x11f8 > [ 78.345599] ksys_ioctl+0xd8/0xf8 > [ 78.348903] __arm64_sys_ioctl+0x2c/0xc8 > [ 78.352812] el0_svc_common.constprop.2+0x88/0x1b0 > [ 78.357583] do_el0_svc+0x44/0xd0 > [ 78.360887] el0_sync_handler+0x14c/0x1d0 > [ 78.364880] el0_sync+0x140/0x180 > [ 78.368185] Code: bad PC value > > SERIAL_PORT_DFNS is not defined on each arch, if it's not defined, > serial8250_set_defaults() won't be called in serial8250_isa_init_ports(), > so the p->serial_in pointer won't be initialized, and it leads a null-ptr-deref. > Fix this problem by calling serial8250_set_defaults() after init uart port. > > Signed-off-by: Yang Yingliang > --- > drivers/tty/serial/8250/8250_core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Does this fix a specific commit, or has this issue always been present? What has caused it to happen now that no one else has seen this? thanks, greg k-h