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 BA7C9C2D0CB for ; Sun, 15 Dec 2019 20:35:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9375E24676 for ; Sun, 15 Dec 2019 20:35:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726598AbfLOUfO (ORCPT ); Sun, 15 Dec 2019 15:35:14 -0500 Received: from mail-io1-f72.google.com ([209.85.166.72]:42814 "EHLO mail-io1-f72.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id 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X-Received: by 2002:a5d:8498:: with SMTP id t24mr15986136iom.164.1576442109907; Sun, 15 Dec 2019 12:35:09 -0800 (PST) Date: Sun, 15 Dec 2019 12:35:09 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000f85c120599c407e4@google.com> Subject: KASAN: use-after-free Read in fbcon_cursor From: syzbot To: b.zolnierkie@samsung.com, daniel.vetter@ffwll.ch, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, 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 Hello, syzbot found the following crash on: HEAD commit: 07c4b9e9 Merge tag 'scsi-fixes' of git://git.kernel.org/pu.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14b61f41e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=79f79de2a27d3e3d dashboard link: https://syzkaller.appspot.com/bug?extid=9116ecc1978ca3a12f43 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=119fa6b6e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+9116ecc1978ca3a12f43@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in fbcon_cursor+0x4ef/0x660 drivers/video/fbdev/core/fbcon.c:1380 Read of size 2 at addr ffff8880959ff0cc by task syz-executor.0/10203 CPU: 1 PID: 10203 Comm: syz-executor.0 Not tainted 5.5.0-rc1-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+0xd4/0x30b 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_load2_noabort+0x14/0x20 mm/kasan/generic_report.c:133 fbcon_cursor+0x4ef/0x660 drivers/video/fbdev/core/fbcon.c:1380 fbcon_scrolldelta+0x679/0x1220 drivers/video/fbdev/core/fbcon.c:2877 fbcon_set_origin+0x43/0x50 drivers/video/fbdev/core/fbcon.c:2928 set_origin+0xf3/0x400 drivers/tty/vt/vt.c:919 vc_do_resize+0xacc/0x1460 drivers/tty/vt/vt.c:1264 vc_resize+0x4d/0x60 drivers/tty/vt/vt.c:1304 vt_ioctl+0x14bb/0x26d0 drivers/tty/vt/vt_ioctl.c:840 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: 0033:0x45a909 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1a84ca0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a909 RDX: 0000000020000000 RSI: 0000000000005609 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1a84ca16d4 R13: 00000000004c7009 R14: 00000000004dd670 R15: 00000000ffffffff Allocated by task 9734: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc+0x163/0x770 mm/slab.c:3665 kmalloc include/linux/slab.h:561 [inline] kzalloc include/linux/slab.h:670 [inline] vc_do_resize+0x262/0x1460 drivers/tty/vt/vt.c:1187 vc_resize+0x4d/0x60 drivers/tty/vt/vt.c:1304 vt_ioctl+0x14bb/0x26d0 drivers/tty/vt/vt_ioctl.c:840 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 Freed by task 10203: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:335 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x2c0 mm/slab.c:3757 vc_do_resize+0xa69/0x1460 drivers/tty/vt/vt.c:1261 vc_resize+0x4d/0x60 drivers/tty/vt/vt.c:1304 vt_ioctl+0x14bb/0x26d0 drivers/tty/vt/vt_ioctl.c:840 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 The buggy address belongs to the object at ffff8880959ff0c0 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 12 bytes inside of 32-byte region [ffff8880959ff0c0, ffff8880959ff0e0) The buggy address belongs to the page: page:ffffea0002567fc0 refcount:1 mapcount:0 mapping:ffff8880aa4001c0 index:0xffff8880959fffc1 raw: 00fffe0000000200 ffffea00027c7748 ffffea000276ee08 ffff8880aa4001c0 raw: ffff8880959fffc1 ffff8880959ff000 000000010000003f 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880959fef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880959ff000: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc > ffff8880959ff080: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ^ ffff8880959ff100: 00 01 fc fc fc fc fc fc fb fb fb fb fc fc fc fc ffff8880959ff180: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ================================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches