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 80D65C43603 for ; Mon, 9 Dec 2019 04:27:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E15220726 for ; Mon, 9 Dec 2019 04:27:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727056AbfLIE1L (ORCPT ); Sun, 8 Dec 2019 23:27:11 -0500 Received: from mail-io1-f72.google.com ([209.85.166.72]:40809 "EHLO mail-io1-f72.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726826AbfLIE1K (ORCPT ); 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Sun, 08 Dec 2019 20:27:09 -0800 (PST) Date: Sun, 08 Dec 2019 20:27:09 -0800 In-Reply-To: <00000000000000ffab05992442a7@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000017046a05993dcf90@google.com> Subject: Re: KASAN: global-out-of-bounds Read in fb_pad_aligned_buffer From: syzbot To: b.zolnierkie@samsung.com, daniel.vetter@ffwll.ch, dri-devel@lists.freedesktop.org, kraxel@redhat.com, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, peda@axentia.se, sam@ravnborg.org, syzkaller-bugs@googlegroups.com 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: 9455d25f Merge tag 'ntb-5.5' of git://github.com/jonmason/.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=171e09dae00000 kernel config: https://syzkaller.appspot.com/x/.config?x=7a3b8f5088d4043a dashboard link: https://syzkaller.appspot.com/bug?extid=0568d05e486eee0a1ba2 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15ddeca6e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16df9e41e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+0568d05e486eee0a1ba2@syzkaller.appspotmail.com ================================================================== BUG: KASAN: global-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:655 [inline] BUG: KASAN: global-out-of-bounds in fb_pad_aligned_buffer+0x138/0x160 drivers/video/fbdev/core/fbmem.c:115 Read of size 1 at addr ffffffff8872a77c by task syz-executor208/9953 CPU: 1 PID: 9953 Comm: syz-executor208 Not tainted 5.4.0-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 print_address_description.constprop.0.cold+0x5/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:639 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:132 __fb_pad_aligned_buffer include/linux/fb.h:655 [inline] fb_pad_aligned_buffer+0x138/0x160 drivers/video/fbdev/core/fbmem.c:115 bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:99 [inline] bit_putcs+0xd14/0xf10 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x33c/0x3e0 drivers/video/fbdev/core/fbcon.c:1353 do_update_region+0x42b/0x6f0 drivers/tty/vt/vt.c:677 redraw_screen+0x676/0x7d0 drivers/tty/vt/vt.c:1011 fbcon_do_set_font+0x829/0x960 drivers/video/fbdev/core/fbcon.c:2605 fbcon_copy_font+0x12c/0x190 drivers/video/fbdev/core/fbcon.c:2620 con_font_copy drivers/tty/vt/vt.c:4594 [inline] con_font_op+0x6b2/0x1270 drivers/tty/vt/vt.c:4609 vt_ioctl+0x181a/0x26d0 drivers/tty/vt/vt_ioctl.c:965 tty_ioctl+0xa37/0x14f0 drivers/tty/tty_io.c:2660 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x440269 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 5b 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff65832458 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440269 RDX: 0000000020000000 RSI: 0000000000004b72 RDI: 0000000000000004 RBP: 00000000006cb018 R08: 000000000000000d R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401b50 R13: 0000000000401be0 R14: 0000000000000000 R15: 0000000000000000 The buggy address belongs to the variable: oid_index+0x93c/0xb80 Memory state around the buggy address: ffffffff8872a600: 04 fa fa fa fa fa fa fa 00 01 fa fa fa fa fa fa ffffffff8872a680: 04 fa fa fa fa fa fa fa 04 fa fa fa fa fa fa fa > ffffffff8872a700: 07 fa fa fa fa fa fa fa 04 fa fa fa fa fa fa fa ^ ffffffff8872a780: 05 fa fa fa fa fa fa fa 01 fa fa fa fa fa fa fa ffffffff8872a800: 00 00 02 fa fa fa fa fa 00 00 00 05 fa fa fa fa ==================================================================