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From: bugzilla-daemon@bugzilla.kernel.org
To: kvm@kernel.org
Subject: [Bug 198205] New: infinite loop in vmx_vcpu_run on x86_64
Date: Tue, 19 Dec 2017 18:37:13 +0000	[thread overview]
Message-ID: <bug-198205-28872@https.bugzilla.kernel.org/> (raw)

https://bugzilla.kernel.org/show_bug.cgi?id=198205

            Bug ID: 198205
           Summary: infinite loop in vmx_vcpu_run on x86_64
           Product: Virtualization
           Version: unspecified
    Kernel Version: 4.14.6
          Hardware: x86-64
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: high
          Priority: P1
         Component: kvm
          Assignee: virtualization_kvm@kernel-bugs.osdl.org
          Reporter: aeden@csail.mit.edu
        Regression: No

When I try to ssh into VM, a thread in QEMU 2.10.1 blocks on

ioctl(cpu->kvm_fd, KVM_RUN, arg);

and I can see that a kernel thread is running at 100% constantly in htop(1).
The ssh command never succeeds, and all of my other ssh sessions in the VM
become unresponsive. The only thing I can do is reboot the VM via libvirt.

So far I've only seen this happen twice, while running a VM on this kernel
version (4.14.6-1-ARCH) everyday. This time, I got a kernel backtrace via

echo l > /proc/sysrq-trigger

To me, kvm_intel doesn't look like it's making progress. Here's the stacktrace
taken from dmesg(1):

[96492.268071] sysrq: SysRq : Show backtrace of all active CPUs
[96492.268072] NMI backtrace for cpu 3
[96492.268073] CPU: 3 PID: 26664 Comm: bash Tainted: G         C     
4.14.6-1-ARCH #1
[96492.268074] Hardware name: Gigabyte Technology Co., Ltd. Z170X-Gaming
7/Z170X-Gaming 7, BIOS F22f 06/28/2017
[96492.268074] Call Trace:
[96492.268084]  dump_stack+0x5c/0x85
[96492.268085]  nmi_cpu_backtrace+0xbf/0xd0
[96492.268086]  ? irq_force_complete_move+0x100/0x100
[96492.268087]  nmi_trigger_cpumask_backtrace+0xea/0x130
[96492.268089]  ? __handle_sysrq+0x83/0x140
[96492.268089]  __handle_sysrq+0x83/0x140
[96492.268091]  write_sysrq_trigger+0x2b/0x30
[96492.268092]  proc_reg_write+0x3d/0x60
[96492.268093]  __vfs_write+0x33/0x170
[96492.268095]  ? set_close_on_exec+0x30/0x70
[96492.268096]  vfs_write+0xad/0x1a0
[96492.268096]  SyS_write+0x52/0xc0
[96492.268098]  entry_SYSCALL_64_fastpath+0x1a/0xa5
[96492.268099] RIP: 0033:0x7fb7f123dab4
[96492.268099] RSP: 002b:00007fffe871cb18 EFLAGS: 00000246 ORIG_RAX:
0000000000000001
[96492.268100] RAX: ffffffffffffffda RBX: 0000000000000134 RCX:
00007fb7f123dab4
[96492.268100] RDX: 0000000000000002 RSI: 0000000002531260 RDI:
0000000000000001
[96492.268100] RBP: 00000000000000c8 R08: 000000000000000a R09:
000000000255ecb0
[96492.268101] R10: 000000000000000a R11: 0000000000000246 R12:
0000000000000000
[96492.268101] R13: 00007fffe871bf70 R14: 00007fffe871c100 R15:
00007fffe871bf70
[96492.268102] Sending NMI from CPU 3 to CPUs 0-2:
[96492.268105] NMI backtrace for cpu 0
[96492.268106] CPU: 0 PID: 1457 Comm: CPU 1/KVM Tainted: G         C     
4.14.6-1-ARCH #1
[96492.268106] Hardware name: Gigabyte Technology Co., Ltd. Z170X-Gaming
7/Z170X-Gaming 7, BIOS F22f 06/28/2017
[96492.268106] task: ffff984898c06ac0 task.stack: ffffb61b82734000
[96492.268109] RIP: 0010:vmx_complete_atomic_exit+0x77/0xd0 [kvm_intel]
[96492.268110] RSP: 0018:ffffb61b82737cf0 EFLAGS: 00000046
[96492.268110] RAX: 0000000080000202 RBX: 0000000000000000 RCX:
ffff98493b9a8000
[96492.268111] RDX: 0000000000004404 RSI: 0000000000000001 RDI:
ffff98493b9a8000
[96492.268111] RBP: ffff98493b9a8000 R08: 0000000000000000 R09:
0000000000000202
[96492.268111] R10: ffffffff9ad171b0 R11: ffffffff9b13c36d R12:
0000000080000200
[96492.268111] R13: 0000000080000202 R14: 0000000000000050 R15:
0000000000000000
[96492.268112] FS:  00007f18a3f63700(0000) GS:ffff98494ec00000(0000)
knlGS:0000000000000000
[96492.268112] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[96492.268112] CR2: 000000000001d001 CR3: 00000003f7c5f003 CR4:
00000000003626f0
[96492.268113] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[96492.268113] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
0000000000000400
[96492.268113] Call Trace:
[96492.268116]  vmx_vcpu_run+0x305/0x4a0 [kvm_intel]
[96492.268131]  ? kvm_arch_vcpu_ioctl_run+0x538/0x1630 [kvm]
[96492.268136]  ? kvm_arch_vcpu_load+0x69/0x230 [kvm]
[96492.268142]  ? load_fixmap_gdt+0x30/0x40
[96492.268143]  ? __vmx_load_host_state.part.84+0x120/0x1f0 [kvm_intel]
[96492.268148]  ? kvm_arch_vcpu_load+0x84/0x230 [kvm]
[96492.268152]  ? kvm_vcpu_ioctl+0x27e/0x5e0 [kvm]
[96492.268156]  ? kvm_vcpu_ioctl+0x27e/0x5e0 [kvm]
[96492.268157]  ? do_futex+0x429/0xa90
[96492.268158]  ? do_vfs_ioctl+0xa1/0x610
[96492.268159]  ? __fget+0x49/0xb0
[96492.268160]  ? SyS_ioctl+0x74/0x80
[96492.268161]  ? exit_to_usermode_loop+0x94/0xa0
[96492.268162]  ? entry_SYSCALL_64_fastpath+0x1a/0xa5
[96492.268162] Code: 74 66 41 81 e4 00 07 00 80 66 83 fb 29 74 45 41 81 fd 12
03 00 80 74 3c 41 81 fc 00 02 00 80 75 af 48 89 ef e8 bb a7 d0 ff cd 02 <5b> 48
89 ef 5d 41 5c 41 5d e9 bb a7 d0 ff 66 83 fb 29 c7 87 8c 
[96492.268170] NMI backtrace for cpu 1
[96492.268171] CPU: 1 PID: 14521 Comm: Xorg Tainted: G         C     
4.14.6-1-ARCH #1
[96492.268171] Hardware name: Gigabyte Technology Co., Ltd. Z170X-Gaming
7/Z170X-Gaming 7, BIOS F22f 06/28/2017
[96492.268172] task: ffff98470c54db80 task.stack: ffffb61b81908000
[96492.268186] RIP: 0010:fw_domains_get+0x11e/0x1d0 [i915]
[96492.268187] RSP: 0018:ffff98494ec83ec0 EFLAGS: 00000086
[96492.268187] RAX: 000057c25b5d24fb RBX: ffff98493bc88000 RCX:
000000000000001f
[96492.268187] RDX: 0000000000000000 RSI: fffffffa093f71b2 RDI:
000000001fefa611
[96492.268188] RBP: 0000000000000000 R08: 0000000000000001 R09:
0000000000000001
[96492.268188] R10: ffff98494ec83ea0 R11: ffffb61b8190baf8 R12:
ffff98493bc88728
[96492.268188] R13: 000057c25b5bf754 R14: 0000000000000000 R15:
00000000ffffffff
[96492.268189] FS:  00007fc598d14940(0000) GS:ffff98494ec80000(0000)
knlGS:0000000000000000
[96492.268189] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[96492.268189] CR2: 00007f5ea7ef93b8 CR3: 000000042d4c8002 CR4:
00000000003626e0
[96492.268190] Call Trace:
[96492.268191]  <IRQ>
[96492.268201]  intel_uncore_forcewake_get.part.8+0x41/0xa0 [i915]
[96492.268210]  intel_lrc_irq_handler+0x2c/0x370 [i915]
[96492.268211]  ? hrtimer_wakeup+0x1e/0x30
[96492.268212]  ? ktime_get+0x3b/0x90
[96492.268213]  tasklet_hi_action+0x59/0x110
[96492.268214]  __do_softirq+0xd9/0x2da
[96492.268215]  do_softirq_own_stack+0x2a/0x40
[96492.268216]  </IRQ>
[96492.268216]  do_softirq.part.17+0x49/0x50
[96492.268217]  __local_bh_enable_ip+0x67/0x70
[96492.268225]  i915_gem_do_execbuffer+0x794/0x10e0 [i915]
[96492.268227]  ? ___slab_alloc+0xf3/0x4b0
[96492.268228]  ? ___slab_alloc+0xf3/0x4b0
[96492.268228]  ? kmem_cache_free+0x1d1/0x1f0
[96492.268235]  ? i915_gem_execbuffer2+0x5d/0x390 [i915]
[96492.268242]  ? i915_gem_execbuffer2+0x5d/0x390 [i915]
[96492.268249]  i915_gem_execbuffer2+0x1b7/0x390 [i915]
[96492.268255]  ? i915_gem_execbuffer+0x2d0/0x2d0 [i915]
[96492.268265]  drm_ioctl_kernel+0x59/0xb0 [drm]
[96492.268269]  drm_ioctl+0x2d5/0x370 [drm]
[96492.268276]  ? i915_gem_execbuffer+0x2d0/0x2d0 [i915]
[96492.268276]  ? hrtimer_start_range_ns+0x1b3/0x330
[96492.268278]  do_vfs_ioctl+0xa1/0x610
[96492.268279]  ? __sys_recvmsg+0x4e/0x90
[96492.268279]  ? __sys_recvmsg+0x7d/0x90
[96492.268280]  SyS_ioctl+0x74/0x80
[96492.268281]  entry_SYSCALL_64_fastpath+0x1a/0xa5
[96492.268281] RIP: 0033:0x7fc596b11337
[96492.268282] RSP: 002b:00007fff81f349e8 EFLAGS: 00003246 ORIG_RAX:
0000000000000010
[96492.268282] RAX: ffffffffffffffda RBX: 0000000000000001 RCX:
00007fc596b11337
[96492.268282] RDX: 00007fff81f34a20 RSI: 0000000040406469 RDI:
000000000000000d
[96492.268283] RBP: 000055c3b68ed610 R08: 0000000000000000 R09:
00007fc598ddeee0
[96492.268283] R10: 0000000000003fb0 R11: 0000000000003246 R12:
000055c3b62eab10
[96492.268283] R13: 000055c3b65806c0 R14: 000000000000001d R15:
0000000000000000
[96492.268284] Code: 89 c5 eb 0d 4c 29 e8 48 3d 7f f0 fa 02 77 77 f3 90 65 8b
3d 7d 74 51 3f e8 40 98 5b df 41 8b 54 24 54 48 03 93 90 06 00 00 8b 12 <83> e2
01 74 d4 45 85 f6 75 95 8b 44 24 04 09 83 18 07 00 00 48 
[96492.268292] NMI backtrace for cpu 2 skipped: idling at pc 0xffffffffa0678b05


Here's the QEMU stacktrace after attaching with gdb:
#0  0x00007f18b08f0337 in ioctl () at /usr/lib/libc.so.6
#1  0x000055f01bb9589b in kvm_vcpu_ioctl ()
#2  0x000055f01bb959e2 in kvm_cpu_exec ()
#3  0x000055f01bb72fa5 in  ()
#4  0x00007f18b0bc208a in start_thread () at /usr/lib/libpthread.so.0
#5  0x00007f18b08f942f in clone () at /usr/lib/libc.so.6

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             reply	other threads:[~2017-12-19 18:37 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-19 18:37 bugzilla-daemon [this message]
2017-12-19 20:05 ` [Bug 198205] infinite loop in vmx_vcpu_run on x86_64 bugzilla-daemon
2018-01-07 13:54 ` bugzilla-daemon
2018-01-07 14:13 ` bugzilla-daemon
2018-01-11 21:16 ` bugzilla-daemon

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