On Mon, Aug 30, 2021, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 3f5ad13cb012 Merge tag 'scsi-fixes' of git://git.kernel.or.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=156f9a4d300000 > kernel config: https://syzkaller.appspot.com/x/.config?x=94074b5caf8665c7 > dashboard link: https://syzkaller.appspot.com/bug?extid=200c08e88ae818f849ce > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13848dfe300000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=136d69e1300000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+200c08e88ae818f849ce@xxxxxxxxxxxxxxxxxxxxxxxxx > > L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details. > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 8469 at arch/x86/kvm/x86.c:525 exception_type+0x98/0xb0 arch/x86/kvm/x86.c:525 > Modules linked in: > CPU: 1 PID: 8469 Comm: syz-executor531 Not tainted 5.14.0-rc7-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:exception_type+0x98/0xb0 arch/x86/kvm/x86.c:525 > Code: 31 ff 45 31 ed 44 89 e6 e8 25 75 69 00 45 85 e4 41 0f 95 c5 45 01 ed e8 d6 6d 69 00 44 89 e8 5b 41 5c 41 5d c3 e8 c8 6d 69 00 <0f> 0b e8 c1 6d 69 00 41 bd 03 00 00 00 5b 44 89 e8 41 5c 41 5d c3 > RSP: 0018:ffffc90000f1f8f0 EFLAGS: 00010293 > RAX: 0000000000000000 RBX: 00000000000000a2 RCX: 0000000000000000 > RDX: ffff888018461c40 RSI: ffffffff810c3b28 RDI: 0000000000000003 > RBP: ffff888020868000 R08: 000000000000001f R09: 00000000000000a2 > R10: ffffffff810c3aaa R11: 0000000000000006 R12: 00000000000000a2 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000040 > FS: 000000000179c300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007fffd362aad8 CR3: 00000000182ef000 CR4: 00000000001526e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > x86_emulate_instruction+0xef6/0x1460 arch/x86/kvm/x86.c:7853 LOL, syzbot configures the VM with MAXPHYADDR=1 and hilarity ensues. The non-nested translate_gfn() fails to prepare the #PF, and also doesn't check allow_smaller_maxphyaddr. I should get a series out today to clean up the mess. > kvm_mmu_page_fault+0x2f0/0x1810 arch/x86/kvm/mmu/mmu.c:5199 > handle_ept_misconfig+0xdf/0x3e0 arch/x86/kvm/vmx/vmx.c:5336 > __vmx_handle_exit arch/x86/kvm/vmx/vmx.c:6021 [inline] > vmx_handle_exit+0x336/0x1800 arch/x86/kvm/vmx/vmx.c:6038 > vcpu_enter_guest+0x2a1c/0x4430 arch/x86/kvm/x86.c:9712 > vcpu_run arch/x86/kvm/x86.c:9779 [inline] > kvm_arch_vcpu_ioctl_run+0x47d/0x1b20 arch/x86/kvm/x86.c:10010 > kvm_vcpu_ioctl+0x49e/0xe50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3652 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:1069 [inline] > __se_sys_ioctl fs/ioctl.c:1055 [inline] > __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x441159 > Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fffd362c598 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 0000000000441159 > RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 > RBP: 0000000000404c50 R08: 0000000000400488 R09: 0000000000400488 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000404ce0 > R13: 0000000000000000 R14: 00000000004ae018 R15: 0000000000400488 > > > --- > This report 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@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > syzbot can test patches for this issue, for details see: > https://goo.gl/tpsmEJ#testing-patches
