[vfio-users] Soft lockup on archlinux 4.1.10-1-vfio-lts kernel

[Lucas Kückelhaus]

Hi,

I'm trying to run an Archlinux host on kernel 4.1.10-1-vfio-lts (Mark 
Weiman's custom repo) because I'm unable to boot a GPU-assigned VM on 
4.2.3-1-vfio.

The VM boots fine and works for a while, but the computer sporadically 
crashes with the following:


Oct 22 21:43:37 kvmhost kernel: NMI watchdog: BUG: soft lockup - CPU#4 
stuck for 22s! [swapper/4:0]
Oct 22 21:43:39 kvmhost kernel: Modules linked in: veth vhost_net vhost 
macvtap macvlan tun bridge stp llc nls_iso8859_1 nls_cp437 vfat fat 
iTCO_wdt iTCO_vendor_support nouveau snd_hda_codec_hdmi intel_rapl 
iosf_mbi x86_pkg_temp_thermal intel_powerclamp coretemp mxm_wmi snd_hda_
Oct 22 21:43:39 kvmhost kernel:  sch_fq_codel fuse nfsd nfs auth_rpcgss 
oid_registry nfs_acl lockd grace sunrpc fscache ip_tables x_tables ext4 
crc16 mbcache jbd2 dm_mod hid_logitech_hidpp hid_logitech_dj hid_generic 
usbhid hid sd_mod uas usb_storage atkbd libps2 crc32c_intel ah
Oct 22 21:43:39 kvmhost kernel: CPU: 4 PID: 0 Comm: swapper/4 Tainted: G 
             L  4.1.10-1-vfio-lts #1
Oct 22 21:43:39 kvmhost kernel: Hardware name: To Be Filled By O.E.M. To 
Be Filled By O.E.M./Z77 Extreme4, BIOS P2.30 09/21/2012
Oct 22 21:43:39 kvmhost kernel: task: ffff88080b119460 ti: 
ffff88080b124000 task.ti: ffff88080b124000
Oct 22 21:43:39 kvmhost kernel: RIP: 0010:[<ffffffff810f6770>]  
[<ffffffff810f6770>] try_to_del_timer_sync+0x0/0xa0
Oct 22 21:43:39 kvmhost kernel: RSP: 0018:ffff88082f303db0  EFLAGS: 
00000286
Oct 22 21:43:39 kvmhost kernel: RAX: 00000000ffffffff RBX: 
0000000000000286 RCX: 0000000000000000
Oct 22 21:43:39 kvmhost kernel: RDX: 00000000000000bf RSI: 
0000000000000286 RDI: ffff880270fa8428
Oct 22 21:43:39 kvmhost kernel: RBP: ffff88082f303dc8 R08: 
0000000000002710 R09: ffff88082f30e780
Oct 22 21:43:39 kvmhost kernel: R10: 0000000000000000 R11: 
0000000000000004 R12: ffff88082f303d28
Oct 22 21:43:39 kvmhost kernel: R13: ffffffff815f13de R14: 
ffff88082f303dc8 R15: ffff880270fa8428
Oct 22 21:43:39 kvmhost kernel: FS:  0000000000000000(0000) 
GS:ffff88082f300000(0000) knlGS:0000000000000000
Oct 22 21:43:39 kvmhost kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 
0000000080050033
Oct 22 21:43:39 kvmhost kernel: CR2: 00007fc2d6f6da28 CR3: 
000000029c65c000 CR4: 00000000001426e0
Oct 22 21:43:39 kvmhost kernel: Stack:
Oct 22 21:43:39 kvmhost kernel:  ffffffff810f6872 ffff88082f303e38 
ffff880270fa8390 ffff88082f303df8
Oct 22 21:43:39 kvmhost kernel:  ffffffff8152a16f ffff880270fa8390 
ffff8805b3bab800 ffff880270d20000
Oct 22 21:43:39 kvmhost kernel:  0000000000000001 ffff88082f303e38 
ffffffff8152a3e7 ffff88082f3107e0
Oct 22 21:43:39 kvmhost kernel: Call Trace:
Oct 22 21:43:39 kvmhost kernel:  <IRQ>
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff810f6872>] ? 
del_timer_sync+0x62/0x70
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff8152a16f>] 
inet_csk_reqsk_queue_drop+0xbf/0x240
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff8152a3e7>] 
reqsk_timer_handler+0xf7/0x2e0
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff8152a2f0>] ? 
inet_csk_reqsk_queue_drop+0x240/0x240
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff810f64c8>] 
call_timer_fn+0x48/0x160
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff8152a2f0>] ? 
inet_csk_reqsk_queue_drop+0x240/0x240
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff810f6bd4>] 
run_timer_softirq+0x284/0x330
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff81086711>] 
__do_softirq+0xf1/0x2e0
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff81086acd>] irq_exit+0xbd/0xc0
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff815f31d5>] 
smp_apic_timer_interrupt+0x55/0x70
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff815f13de>] 
apic_timer_interrupt+0x6e/0x80
Oct 22 21:43:39 kvmhost kernel:  <EOI>
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff81021c1d>] ? 
native_sched_clock+0x2d/0xa0
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff81490c81>] ? 
cpuidle_enter_state+0xa1/0x250
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff81490c53>] ? 
cpuidle_enter_state+0x73/0x250
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff81490e8a>] 
cpuidle_enter+0x2a/0x30
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff810cb36c>] 
cpu_startup_entry+0x32c/0x460
Oct 22 21:43:39 kvmhost kernel:  [<ffffffff81055f7e>] 
start_secondary+0x19e/0x1e0
Oct 22 21:43:39 kvmhost kernel: Code: 4d d8 65 48 33 0c 25 28 00 00 00 
44 89 e0 75 0b 48 83 c4 18 5b 41 5c 41 5d 5d c3 e8 1b b8 f8 ff 90 66 2e 
0f 1f 84 00 00 00 00 00 <0f> 1f 44 00 00 55 48 89 e5 41 54 53 48 81 ec 
30 10 00 00 48 83



This happens for all cores and it locks up the entire system. I don't 
know what to do. On 4.2.3-1-vfio I have no hangups and all my non-vfio 
VMs work perfectly fine.

Thank you,
Lucas Kückelhaus