other: 0.123
device: 0.092
boot: 0.092
KVM: 0.088
PID: 0.088
semantic: 0.081
permissions: 0.073
performance: 0.068
graphic: 0.052
socket: 0.050
network: 0.049
files: 0.049
debug: 0.047
vnc: 0.047
KVM: 0.388
debug: 0.271
boot: 0.236
PID: 0.021
performance: 0.018
other: 0.011
files: 0.011
semantic: 0.011
device: 0.009
graphic: 0.005
socket: 0.005
network: 0.005
permissions: 0.005
vnc: 0.003

qemu-system-s390x: asserts while booting Debian Stretch installer

QEMU 2.9.0 (Arch Linux) asserts when I try to install Debian Stretch.

Steps to reproduce:

wget http://ftp.debian.org/debian/dists/stretch/main/installer-s390x/current/images/generic/initrd.debian
wget http://ftp.debian.org/debian/dists/stretch/main/installer-s390x/current/images/generic/kernel.debian
qemu-img create -f qcow2 hda.qcow2 80G
qemu-system-s390x -kernel kernel.debian -initrd initrd.debian -nographic -drive file=hda.qcow2

Output:

[    0.051915] Linux version 4.9.0-3-s390x (<email address hidden>) (gcc version 6.3.0 20170516 (Debian 6.3.0-18) ) #1 SMP Debian 4.9.30-2 (2017-06-12)
[    0.053000] setup: Linux is running under KVM in 64-bit mode
[    0.053780] setup: Max memory size: 128MB
[    0.067239] Write protected kernel read-only data: 8848k
[    0.082461] Zone ranges:
[    0.083717]   DMA      [mem 0x0000000000000000-0x000000007fffffff]
[    0.084163]   Normal   empty
[    0.084185] Movable zone start for each node
[    0.084223] Early memory node ranges
[    0.084306]   node   0: [mem 0x0000000000000000-0x0000000007ffffff]
[    0.084468] Initmem setup node 0 [mem 0x0000000000000000-0x0000000007ffffff]
[    0.087697] percpu: Embedded 19 pages/cpu @0000000007f87000 s40704 r8192 d28928 u77824
[    0.088991] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 32256
[    0.089108] Kernel command line: 
[    0.096684] PID hash table entries: 512 (order: 0, 4096 bytes)
[    0.096853] Dentry cache hash table entries: 16384 (order: 5, 131072 bytes)
[    0.097041] Inode-cache hash table entries: 8192 (order: 4, 65536 bytes)
[    0.102453] Memory: 105164K/131072K available (6060K kernel code, 802K rwdata, 2784K rodata, 508K init, 648K bss, 25908K reserved, 0K cma-reserved)
[    0.109112] Hierarchical RCU implementation.
[    0.109134] 	Build-time adjustment of leaf fanout to 64.
[    0.109155] 	RCU restricting CPUs from NR_CPUS=256 to nr_cpu_ids=2.
[    0.109194] RCU: Adjusting geometry for rcu_fanout_leaf=64, nr_cpu_ids=2
[    0.122047] NR_IRQS:3 nr_irqs:3 3
[    0.124317] clocksource: tod: mask: 0xffffffffffffffff max_cycles: 0x3b0a9be803b0a9, max_idle_ns: 1805497147909793 ns
[    0.138366] console [ttyS1] enabled
[    0.139126] pid_max: default: 32768 minimum: 301
[    0.143164] Security Framework initialized
[    0.143215] Yama: disabled by default; enable with sysctl kernel.yama.*
[    0.143955] AppArmor: AppArmor disabled by boot time parameter
[    0.144489] Mount-cache hash table entries: 512 (order: 0, 4096 bytes)
[    0.144538] Mountpoint-cache hash table entries: 512 (order: 0, 4096 bytes)
[    0.156937] ftrace: allocating 19165 entries in 75 pages
[    0.408921] cpu: 1 configured CPUs, 0 standby CPUs
[    0.433942] Brought up 1 CPUs
[    0.451811] devtmpfs: initialized
[    0.467021] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
[    0.467549] futex hash table entries: 512 (order: 5, 131072 bytes)
[    0.476626] NET: Registered protocol family 16
[    0.482575] The s390-virtio transport is deprecated. Please switch to a modern host providing virtio-ccw.
[    0.693017] VFS: Disk quotas dquot_6.6.0
[    0.693296] VFS: Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
[    0.695029] hugetlbfs: disabling because there are no supported hugepage sizes
[    0.703040] NET: Registered protocol family 2
[    0.709803] TCP established hash table entries: 1024 (order: 1, 8192 bytes)
[    0.710003] TCP bind hash table entries: 1024 (order: 2, 16384 bytes)
[    0.710134] TCP: Hash tables configured (established 1024 bind 1024)
[    0.710879] UDP hash table entries: 256 (order: 1, 8192 bytes)
[    0.711005] UDP-Lite hash table entries: 256 (order: 1, 8192 bytes)
[    0.712409] NET: Registered protocol family 1
[    0.717432] Unpacking initramfs...
[    1.308935] random: fast init done
[    1.597369] Freeing initrd memory: 10152K (0000000000f90000 - 000000000197a000)
[    1.600200] hypfs: The hardware system does not support hypfs
[    1.601718] hypfs: Initialization of hypfs failed with rc=-61
[    1.605317] audit: initializing netlink subsys (disabled)
[    1.606211] audit: type=2000 audit(1497977949.601:1): initialized
[    1.611137] workingset: timestamp_bits=46 max_order=15 bucket_order=0
[    1.612066] zbud: loaded
[    1.642108] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252)
[    1.643111] io scheduler noop registered
[    1.643160] io scheduler deadline registered
[    1.643383] io scheduler cfq registered (default)
[    1.644143] pci_hotplug: PCI Hot Plug PCI Core version: 0.5
[    1.644221] pciehp: PCI Express Hot Plug Controller Driver version: 0.4
[    1.645626] hvc_iucv: The z/VM IUCV HVC device driver cannot be used without z/VM
[    1.647547] mousedev: PS/2 mouse device common for all mice
[    1.649359] ledtrig-cpu: registered to indicate activity on CPUs
[    1.649884] cio: Channel measurement facility initialized using format extended (mode autodetected)
[    1.657228] NET: Registered protocol family 10
[    1.663924] mip6: Mobile IPv6
[    1.664068] NET: Registered protocol family 17
[    1.664195] mpls_gso: MPLS GSO support
[    1.667936] registered taskstats version 1
[    1.669547] zswap: loaded using pool lzo/zbud
[    1.674474] ima: No TPM chip found, activating TPM-bypass!
[    1.739953] Freeing unused kernel memory: 508K (0000000000a6f000 - 0000000000aee000)
[    1.740381] Write protected read-only-after-init data: 4k
**
ERROR:/build/qemu/src/qemu-2.9.0/translate-common.c:34:tcg_handle_interrupt: assertion failed: (qemu_mutex_iothread_locked())
[1]    13880 abort (core dumped)  qemu-system-s390x -kernel kernel.debian -initrd initrd.debian -nographic 

Trace:
#0  0x00007ffff10fb670 in raise () at /usr/lib/libc.so.6
#1  0x00007ffff10fcd00 in abort () at /usr/lib/libc.so.6
#2  0x00007ffff35dfc9d in g_assertion_message () at /usr/lib/libglib-2.0.so.0
#3  0x00007ffff35dfd2a in g_assertion_message_expr () at /usr/lib/libglib-2.0.so.0
#4  0x00005555556abb84 in  ()
#5  0x000055555572ab73 in css_adapter_interrupt ()
#6  0x000055555571be68 in virtio_notify ()
#7  0x00005555556f84ce in  ()
#8  0x00005555556f9afd in  ()
#9  0x00005555556fa78f in virtio_blk_handle_vq ()
#10 0x000055555571b7f1 in virtio_queue_notify ()
#11 0x000055555572ceb7 in  ()
#12 0x0000555555726f86 in s390_virtio_hypercall ()
#13 0x0000555555752c85 in helper_diag ()
#14 0x00007fffe46664bf in code_gen_buffer ()
#15 0x00005555556ab2f5 in cpu_exec ()
#16 0x00005555556ce08d in  ()
#17 0x00007ffff1474297 in start_thread () at /usr/lib/libpthread.so.0
#18 0x00007ffff11b525f in clone () at /usr/lib/libc.so.6

Thanks for the bug report! If you've got a chance to use the latest development version of QEMU from the git repository instead, could you please try whether you could also reproduce the problem there? I think we've already got the fix for this problem in there:

http://git.qemu.org/?p=qemu.git;a=commitdiff;h=2cf9953beebd194a432ebd

Thank you for the super quick response.
I can confirm that the bug is fixed with the current version in git.