linux-kernel - Re: kvm: GPF in native_write

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Date:   Tue, 31 Oct 2017 19:10:59 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     Dmitry Vyukov <dvyukov@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        KVM list <kvm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Xiao Guangrong <guangrong.xiao@...ux.intel.com>,
        Haozhong Zhang <haozhong.zhang@...el.com>,
        David Hildenbrand <david@...hat.com>,
        syzkaller <syzkaller@...glegroups.com>
Subject: Re: kvm: GPF in native_write_cr4

2017-10-31 17:59 GMT+08:00 Dmitry Vyukov <dvyukov@...gle.com>:
> 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.
>

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 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 ]---