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=-5.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS 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 5AB06C32771 for ; Thu, 9 Jan 2020 09:04:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38AAC20678 for ; Thu, 9 Jan 2020 09:04:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729112AbgAIJEM (ORCPT ); Thu, 9 Jan 2020 04:04:12 -0500 Received: from mail-il1-f198.google.com ([209.85.166.198]:37649 "EHLO mail-il1-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728593AbgAIJEL (ORCPT ); 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Thu, 09 Jan 2020 01:04:10 -0800 (PST) Date: Thu, 09 Jan 2020 01:04:10 -0800 In-Reply-To: <00000000000038e517059bb08615@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000dba877059bb14a54@google.com> Subject: Re: KASAN: null-ptr-deref Read in insert_char From: syzbot To: daniel.vetter@ffwll.ch, ghalat@redhat.com, gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org, nico@fluxnic.net, sam@ravnborg.org, syzkaller-bugs@googlegroups.com, textshell@uchuujin.de Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: b07f636f Merge tag 'tpmdd-next-20200108' of git://git.infr.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=102e1c85e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=18698c0c240ba616 dashboard link: https://syzkaller.appspot.com/bug?extid=7416b988c249396c5e2c compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1716da9ee00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10a9cc85e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+7416b988c249396c5e2c@syzkaller.appspotmail.com ================================================================== BUG: KASAN: null-ptr-deref in memmove include/linux/string.h:395 [inline] BUG: KASAN: null-ptr-deref in scr_memmovew include/linux/vt_buffer.h:68 [inline] BUG: KASAN: null-ptr-deref in insert_char+0x206/0x400 drivers/tty/vt/vt.c:839 Read of size 4294967294 at addr 0000000000000010 by task syz-executor700/10454 CPU: 0 PID: 10454 Comm: syz-executor700 Not tainted 5.5.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 __kasan_report.cold+0x5/0x41 mm/kasan/report.c:510 kasan_report+0x12/0x20 mm/kasan/common.c:639 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192 memmove+0x24/0x50 mm/kasan/common.c:116 memmove include/linux/string.h:395 [inline] scr_memmovew include/linux/vt_buffer.h:68 [inline] insert_char+0x206/0x400 drivers/tty/vt/vt.c:839 csi_at drivers/tty/vt/vt.c:1964 [inline] do_con_trol+0x41a6/0x61b0 drivers/tty/vt/vt.c:2431 do_con_write.part.0+0xfd9/0x1ef0 drivers/tty/vt/vt.c:2797 do_con_write drivers/tty/vt/vt.c:2565 [inline] con_write+0x46/0xd0 drivers/tty/vt/vt.c:3135 process_output_block drivers/tty/n_tty.c:595 [inline] n_tty_write+0x40e/0x1080 drivers/tty/n_tty.c:2333 do_tty_write drivers/tty/tty_io.c:962 [inline] tty_write+0x496/0x7f0 drivers/tty/tty_io.c:1046 __vfs_write+0x8a/0x110 fs/read_write.c:494 vfs_write+0x268/0x5d0 fs/read_write.c:558 ksys_write+0x14f/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:620 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x447b99 Code: e8 cc 14 03 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 ab 0e fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ff82cd33db8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000006ddc28 RCX: 0000000000447b99 RDX: 0000000000000078 RSI: 0000000020000000 RDI: 0000000000000004 RBP: 00000000006ddc20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006ddc2c R13: 00007ffff0ce099f R14: 00007ff82cd349c0 R15: 0000000000000000 ==================================================================