From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f70.google.com (mail-it0-f70.google.com [209.85.214.70]) by kanga.kvack.org (Postfix) with ESMTP id A33B16B0003 for ; Sat, 26 May 2018 13:42:03 -0400 (EDT) Received: by mail-it0-f70.google.com with SMTP id e10-v6so6985969itf.7 for ; Sat, 26 May 2018 10:42:03 -0700 (PDT) Received: from mail-sor-f69.google.com (mail-sor-f69.google.com. [209.85.220.69]) by mx.google.com with SMTPS id h131-v6sor4728870itc.132.2018.05.26.10.42.02 for (Google Transport Security); Sat, 26 May 2018 10:42:02 -0700 (PDT) MIME-Version: 1.0 Date: Sat, 26 May 2018 10:42:02 -0700 Message-ID: <000000000000f1e2b9056d1f663c@google.com> Subject: WARNING: bad usercopy in __kvm_write_guest_page From: syzbot Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: owner-linux-mm@kvack.org List-ID: To: keescook@chromium.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com Hello, syzbot found the following crash on: HEAD commit: 73fcb1a370c7 Merge branch 'akpm' (patches from Andrew) git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15b3a827800000 kernel config: https://syzkaller.appspot.com/x/.config?x=f3b4e30da84ec1ed dashboard link: https://syzkaller.appspot.com/bug?extid=083f3b88782aa3a46bdb compiler: gcc (GCC) 8.0.1 20180413 (experimental) syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=1027dbcf800000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=159eff97800000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+083f3b88782aa3a46bdb@syzkaller.appspotmail.com random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) ------------[ cut here ]------------ Bad or missing usercopy whitelist? Kernel memory exposure attempt detected from SLAB object 'kvm_vcpu' (offset 23192, size 8)! WARNING: CPU: 0 PID: 4554 at mm/usercopy.c:81 usercopy_warn+0xf5/0x120 mm/usercopy.c:76 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 4554 Comm: syz-executor726 Not tainted 4.17.0-rc5+ #58 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+0x1b9/0x294 lib/dump_stack.c:113 panic+0x22f/0x4de kernel/panic.c:184 __warn.cold.8+0x163/0x1b3 kernel/panic.c:536 report_bug+0x252/0x2d0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992 RIP: 0010:usercopy_warn+0xf5/0x120 mm/usercopy.c:76 RSP: 0018:ffff8801ad54f0b0 EFLAGS: 00010286 RAX: 000000000000007e RBX: ffffffff889d52f0 RCX: ffffffff8160aa5d RDX: 0000000000000000 RSI: ffffffff8160f711 RDI: ffff8801ad54ec10 RBP: ffff8801ad54f110 R08: ffff8801d96c8680 R09: 0000000000000006 R10: ffff8801d96c8680 R11: 0000000000000000 R12: ffffffff87d2fa60 R13: ffffffff87c19ec0 R14: 0000000000000000 R15: 0000000000000008 __check_heap_object+0x89/0xb5 mm/slab.c:4440 check_heap_object mm/usercopy.c:236 [inline] __check_object_size+0x4c7/0x5d9 mm/usercopy.c:259 check_object_size include/linux/thread_info.h:108 [inline] __copy_to_user include/linux/uaccess.h:104 [inline] __kvm_write_guest_page+0x90/0x140 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1828 kvm_vcpu_write_guest_page arch/x86/kvm/../../../virt/kvm/kvm_main.c:1849 [inline] kvm_vcpu_write_guest+0x65/0xe0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1883 kvm_write_guest_virt_system+0x8a/0x190 arch/x86/kvm/x86.c:4843 handle_vmptrst+0x1d2/0x260 arch/x86/kvm/vmx.c:8196 vmx_handle_exit+0x2c0/0x17b0 arch/x86/kvm/vmx.c:9234 vcpu_enter_guest+0x13af/0x6060 arch/x86/kvm/x86.c:7503 vcpu_run arch/x86/kvm/x86.c:7565 [inline] kvm_arch_vcpu_ioctl_run+0x33e/0x1690 arch/x86/kvm/x86.c:7742 kvm_vcpu_ioctl+0x79d/0x12e0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2560 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1cf/0x16a0 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 __do_sys_ioctl fs/ioctl.c:708 [inline] __se_sys_ioctl fs/ioctl.c:706 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x443039 RSP: 002b:00007ffc272242b8 EFLAGS: 00000286 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000443039 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 RBP: 00000000006cd018 R08: 0000000020000580 R09: 0000000020000580 R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000404080 R13: 0000000000404110 R14: 0000000000000000 R15: 0000000000000000 Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: disabled Rebooting in 86400 seconds.. --- 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#bug-status-tracking for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches