On Mon, Apr 2, 2018 at 8:04 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > On Mon, Apr 2, 2018 at 6:36 PM, Christopherson, Sean J > <sean.j.christopherson@xxxxxxxxx> wrote: >> On Sat, 2018-03-31, Dmitry Vyukov wrote: >>> On Wed, Dec 27, 2017 at 7:31 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: >>> > On Tue, Dec 26, 2017 at 9:52 AM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: >>> >> On Wed, Dec 20, 2017 at 8:54 AM, Wanpeng Li <kernellwp@xxxxxxxxx> wrote: >>> >>> 2017-12-20 15:49 GMT+08:00 syzbot >>> >>> <bot+ab09454bf4b7a7f8ce7e5e8d97e644d3314a0799@xxxxxxxxxxxxxxxxxxxxxxxxx>: >>> >>>> Hello, >>> >>>> >>> >>>> syzkaller hit the following crash on >>> >>>> f6f3732162b5ae3c771b9285a5a32d72b8586920 >>> >>>> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master >>> >>>> compiler: gcc (GCC) 7.1.1 20170620 >>> >>>> .config is attached >>> >>>> Raw console output is attached. >>> >>>> C reproducer is attached >>> >>>> syzkaller reproducer is attached. See https://goo.gl/kgGztJ >>> >>>> for information about syzkaller reproducers >>> >>>> >>> >>>> >>> >>> >>> >>> I will have a look again, you continue to run it in kvm guest, right? >>> >> >>> >> >>> >> Our test machines are GCE VMs, so yes, the kernel that catches GPF is >>> >> run as kvm guest. >>> > >>> > up >>> > >>> > one of top crashers with 50K crashes >>> >>> >>> This sets a new record of 130000 crashed machines on syzbot infrastructure: >>> >>> https://syzkaller.appspot.com/bug?id=2bf7b7983c2398ec6f0c4c6c87cb50223e8873f8 >> >> This is more than likely a known bug in the GCE kernel, i.e. the L0 >> kernel. The fix that Haozhong referenced needs to be applied to the >> L0 kernel (GCE), the L1 kernel (Syzkaller) is irrelevant. You said >> that you double checked an upstream kernel, but I'm assuming you were >> referring to patching the L1 kernel (Syzkaller). >> >> https://lkml.org/lkml/2017/10/31/432 > > Hi Sean, > > Thanks! Either I did not associate these 2 threads as we shuffle > hundreds of bugs, or I did not realize that this needs to be applied > to L0. Anyway... > > I will check with GCE folks. Let's consider this closed for the purpose of syzbot tracking: #syz fix: KVM: nVMX: fix guest CR4 loading when emulating L2 to L1 exit >>> >>>> kvm: KVM_SET_TSS_ADDR need to be called before entering vcpu >>> >>>> kasan: CONFIG_KASAN_INLINE enabled >>> >>>> kasan: GPF could be caused by NULL-ptr deref or user memory access >>> >>>> general protection fault: 0000 [#1] SMP KASAN >>> >>>> Dumping ftrace buffer: >>> >>>> (ftrace buffer empty) >>> >>>> Modules linked in: >>> >>>> CPU: 1 PID: 3142 Comm: syzkaller429302 Not tainted 4.15.0-rc3+ #224 >>> >>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >>> >>>> Google 01/01/2011 >>> >>>> RIP: 0010:native_write_cr4+0x4/0x10 arch/x86/include/asm/special_insns.h:76 >>> >>>> RSP: 0018:ffff8801ca6f75a0 EFLAGS: 00010093 >>> >>>> RAX: ffff8801ca1c8700 RBX: 00000000001606e0 RCX: ffffffff811a2a92 >>> >>>> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000001606e0 >>> >>>> RBP: ffff8801ca6f75a0 R08: 1ffff100394dee0f R09: 0000000000000004 >>> >>>> R10: ffff8801ca6f7510 R11: 0000000000000004 R12: 0000000000000093 >>> >>>> R13: ffff8801ca1c8700 R14: ffff8801db514850 R15: ffff8801db514850 >>> >>>> FS: 0000000001031880(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000 >>> >>>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> >>>> CR2: 0000000000000000 CR3: 0000000005e22006 CR4: 00000000001626e0 >>> >>>> Call Trace: >>> >>>> __write_cr4 arch/x86/include/asm/paravirt.h:76 [inline] >>> >>>> __cr4_set arch/x86/include/asm/tlbflush.h:180 [inline] >>> >>>> cr4_clear_bits arch/x86/include/asm/tlbflush.h:203 [inline] >>> >>>> kvm_cpu_vmxoff arch/x86/kvm/vmx.c:3582 [inline] >>> >>>> hardware_disable+0x34a/0x4b0 arch/x86/kvm/vmx.c:3588 >>> >>>> kvm_arch_hardware_disable+0x35/0xd0 arch/x86/kvm/x86.c:7982 >>> >>>> hardware_disable_nolock+0x30/0x40 >>> >>>> arch/x86/kvm/../../../virt/kvm/kvm_main.c:3310 >>> >>>> on_each_cpu+0xca/0x1b0 kernel/smp.c:604 >>> >>>> hardware_disable_all_nolock+0x3e/0x50 >>> >>>> arch/x86/kvm/../../../virt/kvm/kvm_main.c:3328 >>> >>>> hardware_disable_all arch/x86/kvm/../../../virt/kvm/kvm_main.c:3334 >>> >>>> [inline] >>> >>>> kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:742 [inline] >>> >>>> kvm_put_kvm+0x956/0xdf0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:755 >>> >>>> kvm_vm_release+0x42/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:766 >>> >>>> __fput+0x327/0x7e0 fs/file_table.c:210 >>> >>>> ____fput+0x15/0x20 fs/file_table.c:244 >>> >>>> task_work_run+0x199/0x270 kernel/task_work.c:113 >>> >>>> exit_task_work include/linux/task_work.h:22 [inline] >>> >>>> do_exit+0x9bb/0x1ad0 kernel/exit.c:865 >>> >>>> do_group_exit+0x149/0x400 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/0x96 >>> >>>> RIP: 0033:0x441c78 >>> >>>> RSP: 002b:00007ffe68e20f68 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 >>> >>>> RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000441c78 >>> >>>> RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 >>> >>>> RBP: 00000000006cd018 R08: 00000000000000e7 R09: ffffffffffffffd0 >>> >>>> R10: 0000000000000012 R11: 0000000000000246 R12: 0000000000404080 >>> >>>> R13: 0000000000404110 R14: 0000000000000000 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:76 RSP: >>> >>>> ffff8801ca6f75a0 >>> >>>> ---[ end trace ca14f0c15b26c251 ]--- >>> >>>> >>> >>>> >>> >>>> --- >>> >>>> This bug is generated by a dumb bot. It may contain errors. >>> >>>> See https://goo.gl/tpsmEJ for details. >>> >>>> Direct all questions to syzkaller@xxxxxxxxxxxxxxxx. >>> >>>> Please credit me with: Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx> >>> >>>> >>> >>>> syzbot will keep track of this bug report. >>> >>>> Once a fix for this bug is merged into any tree, reply to this email with: >>> >>>> #syz fix: exact-commit-title >>> >>>> If you want to test a patch for this bug, please reply with: >>> >>>> #syz test: git://repo/address.git branch >>> >>>> and provide the patch inline or as an attachment. >>> >>>> To mark this as a duplicate of another syzbot report, please reply with: >>> >>>> #syz dup: exact-subject-of-another-report >>> >>>> If it's a one-off invalid bug report, please reply with: >>> >>>> #syz invalid >>> >>>> Note: if the crash happens again, it will cause creation of a new bug >>> >>>> report. >>> >>>> Note: all commands must start from beginning of the line in the email body.
