On Tue, Oct 31, 2017 at 2:07 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > On Tue, Oct 31, 2017 at 3:53 PM, Haozhong Zhang > <haozhong.zhang@xxxxxxxxx> wrote: >> Hi Wanpeng, >> >> On 10/31/17 19:10 +0800, Wanpeng Li wrote: >>> 2017-10-31 17:59 GMT+08:00 Dmitry Vyukov <dvyukov@xxxxxxxxxx>: >>> > Hello, >>> > >>> > I am seeing the following crash on upstream >>> > 15f859ae5c43c7f0a064ed92d33f7a5bc5de6de0 (Oct 26). >>> > Reproducer: >>> > https://gist.githubusercontent.com/dvyukov/a9690f90c39c1e3b1b6c7acda2d5ef89/raw/33e07f3d6779005fc475764e0802e4a5aee8d0cf/gistfile1.txt >>> > I run qemu with -append "kvm-intel.nested=1" -enable-kvm -cpu host. My >>> > host cpu is E5-2690. As +Jim pointed out, this is E5-2690 v3 to be more precise. >>> I can't reproduce this w/ latest kvm/queue in both L0 and L1. In >>> addition, there is a commit tries to fix cr4 recently. >>> https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=8eb3f87d903168bdbd1222776a6b1e281f50513e >> >> The calltrace in this bug report is the same as what I got before >> above commit. >> >> In the previous bug, L0 KVM misused L2 CR4 as L1 CR4. When L1 KVM >> tried to clear L1 CR4.VMXE in L1 VM shutdown path, L0 KVM considered >> L1 intended to clear/set other bits as well (because of the wrong L2 >> CR4 was used by L0 KVM as L1 CR4), but changes to extra bits may not >> be allowed against other L1 states. >> >> In my previous fix, I tried to fix one place of such L1/L2 CR4 >> misuse. If there is no other places of CR4 misuse, you may have a look >> at the guest states checked by kvm_set_cr4() against guest CR4 >> changes, and check whether L1 and L2 versions of any of them are >> misused. >> >> It would make the debug easier if we can log which check fails in >> kvm_set_cr4() when the calltrace appears (e.g., by adding printk >> before return 1 in kvm_set_cr4()). >> >> >> Haozhong > > > To double-check I've also tried latest upstream > 5f479447d983111c039f1d6d958553c1ad1b2ff1 (Oct 30) and the bug still > reproduces. So it reproduces with the mentioned fix. > > > >>> The testcast is complex, if the below strace log is as you expected? >>> >>> execve("./a.out", ["./a.out"], [/* 32 vars */]) = 0 >>> uname({sysname="Linux", nodename="kernel", ...}) = 0 >>> brk(NULL) = 0x1d42000 >>> brk(0x1d431c0) = 0x1d431c0 >>> arch_prctl(ARCH_SET_FS, 0x1d42880) = 0 >>> readlink("/proc/self/exe", "/home/kernel/a.out", 4096) = 18 >>> brk(0x1d641c0) = 0x1d641c0 >>> brk(0x1d65000) = 0x1d65000 >>> access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) >>> mmap(0x20000000, 11481088, PROT_READ|PROT_WRITE, >>> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000 >>> openat(AT_FDCWD, "/dev/kvm", O_WRONLY) = 3 >>> ioctl(3, KVM_CREATE_VM or LOGGER_GET_LOG_BUF_SIZE, 0) = 4 >>> ioctl(4, KVM_CREATE_VCPU, 0) = 5 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1230) = 0 >>> ioctl(4, KVM_SET_USER_MEMORY_REGION, 0x7fff5e6c1170) = 0 >>> ioctl(5, KVM_GET_SREGS, 0x7fff5e6c1330) = 0 >>> open("/dev/kvm", O_RDWR) = 6 >>> ioctl(6, KVM_GET_SUPPORTED_CPUID, 0x7fff5e6c1470) = 0 >>> ioctl(5, KVM_SET_CPUID2, 0x7fff5e6c1470) = 0 >>> close(6) = 0 >>> ioctl(5, KVM_SET_MSRS, 0x7fff5e6c0c30) = 5 >>> ioctl(5, KVM_SET_SREGS, 0x7fff5e6c1330) = 0 >>> ioctl(5, KVM_SET_REGS, 0x7fff5e6c1230) = 0 >>> mremap(0x20998000, 4096, 16384, MREMAP_MAYMOVE|MREMAP_FIXED, >>> 0x200fa000) = 0x200fa000 >>> ioctl(5, KVM_RUN, 0) = 0 >>> mbind(0x20000000, 8192, MPOL_DEFAULT 0x20001ff8, 2, MPOL_MF_MOVE) = 0 >>> exit_group(0) = ? >>> +++ exited with 0 +++ >>> i >>> >>> Regards, >>> Wanpeng Li >>> >>> > general protection fault: 0000 [#1] SMP KASAN >>> > Modules linked in: >>> > CPU: 1 PID: 3064 Comm: a.out Not tainted 4.14.0-rc6+ #11 >>> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 >>> > task: ffff880064c203c0 task.stack: ffff880066718000 >>> > RIP: 0010:native_write_cr4+0x4/0x10 arch/x86/include/asm/special_insns.h:75 >>> > RSP: 0018:ffff88006671f598 EFLAGS: 00010097 >>> > RAX: ffff880064c203c0 RBX: 00000000001606e0 RCX: 0000000000000000 >>> > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000001606e0 >>> > RBP: ffff88006671f598 R08: 0000000000000006 R09: 0000000000000006 >>> > R10: ffff880064c203c0 R11: 0000000000000000 R12: 0000000000000001 >>> > R13: ffff88006ca94828 R14: ffff88006ca94850 R15: ffff88006ca80000 >>> > FS: 00000000019cd880(0000) GS:ffff88006ca80000(0000) knlGS:0000000000000000 >>> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> > CR2: 0000000000000000 CR3: 0000000005a22001 CR4: 00000000001626e0 >>> > Call Trace: >>> > __write_cr4 arch/x86/include/asm/paravirt.h:76 [inline] >>> > cr4_clear_bits arch/x86/include/asm/tlbflush.h:197 [inline] >>> > kvm_cpu_vmxoff arch/x86/kvm/vmx.c:3571 [inline] >>> > hardware_disable+0x197/0x210 arch/x86/kvm/vmx.c:3577 >>> > kvm_arch_hardware_disable+0x35/0xd0 arch/x86/kvm/x86.c:7920 >>> > hardware_disable_nolock+0x30/0x40 >>> > arch/x86/kvm/../../../virt/kvm/kvm_main.c:3282 >>> > on_each_cpu+0xca/0x1b0 kernel/smp.c:604 >>> > hardware_disable_all_nolock+0x44/0x60 >>> > arch/x86/kvm/../../../virt/kvm/kvm_main.c:3300 >>> > hardware_disable_all arch/x86/kvm/../../../virt/kvm/kvm_main.c:3306 [inline] >>> > kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:735 [inline] >>> > kvm_put_kvm+0x887/0xe00 arch/x86/kvm/../../../virt/kvm/kvm_main.c:748 >>> > kvm_vm_release+0x42/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:759 >>> > __fput+0x301/0x7e0 fs/file_table.c:210 >>> > ____fput+0x15/0x20 fs/file_table.c:244 >>> > task_work_run+0x19e/0x250 kernel/task_work.c:112 >>> > exit_task_work include/linux/task_work.h:21 [inline] >>> > do_exit+0x99f/0x18b0 kernel/exit.c:865 >>> > do_group_exit+0x14b/0x3f0 kernel/exit.c:968 >>> > SYSC_exit_group kernel/exit.c:979 [inline] >>> > SyS_exit_group+0x1d/0x20 kernel/exit.c:977 >>> > entry_SYSCALL_64_fastpath+0x1f/0xbe >>> > RIP: 0033:0x443849 >>> > RSP: 002b:00007ffe58a95c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 >>> > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000443849 >>> > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 >>> > RBP: 0000000000000086 R08: 000000000000003c R09: 00000000000000e7 >>> > R10: ffffffffffffffc0 R11: 0000000000000246 R12: 0000000000000000 >>> > R13: 0000000000404800 R14: 0000000000404890 R15: 0000000000000000 >>> > Code: 0f 1f 80 00 00 00 00 55 48 89 e5 0f 20 d8 5d c3 0f 1f 80 00 00 >>> > 00 00 55 48 89 e5 0f 22 df 5d c3 0f 1f 80 00 00 00 00 55 48 89 e5 <0f> >>> > 22 e7 5d c3 0f 1f 80 00 00 00 00 55 48 89 e5 44 0f 20 c0 5d >>> > RIP: native_write_cr4+0x4/0x10 arch/x86/include/asm/special_insns.h:75 >>> > RSP: ffff88006671f598 >>> > ---[ end trace 6f9dbcc14aa47936 ]---
