Android Studio emulator: ERROR: detected a hanging thread QEMU2 main loop

RELAX guys!

Actually hanging state may occur

  • at starting of emulator
  • during the run

and this may be after

  • updating packages

  • when you import or open a project into higher version of android studio like 2.4 -> 3.0.1 etc the main reason is that your previous app's state is saved with previous libraries and packages of android studio, So to solve this error is easy i.e

a) Tools->AVD->Edit->advanced settings. choose quick boot instead of cold boot (as answered by Kamel)

OR

b) if you already chosen 'Quick boot' then choose 'Cold boot', and restart emulator, it will work fine.


I found an interim workaround - make sure IPv6 is enabled. 

$ cat /proc/sys/net/ipv6/conf/all/disable_ipv6
0

If you see 1 above, edit your /etc/sysctl.conf file and comment out all the IPv6 disable directives:

# net.ipv6.conf.all.disable_ipv6 = 1
# net.ipv6.conf.default.disable_ipv6 = 1
# net.ipv6.conf.lo.disable_ipv6 = 1

Update Jan 5, '18: At least one user reports that disabling a previously enabled IPv6 has resolved the problem on his system. In that case, you may want to try to reverse the steps above if IPv6 is already enabled on your system and the emulator does not start.

I started experiencing the exact same problem after the most recent update of the Android SDK on my Ubuntu 16.04. The executable doesn't have symbols so I'm not sure how to point the original developer to the root cause, but here is the threads state:

(gdb) info threads
  Id   Target Id         Frame 
  1    Thread 0x7f6d20428700 (LWP 14472) 0x00000000014e8baf in ?? ()
  2    Thread 0x7f6d20c29700 (LWP 14471) syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
* 3    Thread 0x7f6d20c2ad00 (LWP 14470) 0x00007f6d258a27d1 in __GI_ppoll (fds=0x3842bf8, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:50
  4    Thread 0x7f6d1d427700 (LWP 14479) pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
  5    Thread 0x7f6d1649b700 (LWP 14483) pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
  6    Thread 0x7f6d05fe4700 (LWP 14487) __lll_lock_wait () at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
  7    Thread 0x7f6d16c9c700 (LWP 14482) __lll_lock_wait () at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
  8    Thread 0x7f6d1cc26700 (LWP 14480) pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
  9    Thread 0x7f6d1eda9700 (LWP 14478) 0x00007f6d258a270d in poll () at ../sysdeps/unix/syscall-template.S:84
  10   Thread 0x7f6d067e5700 (LWP 14486) 0x00007f6d280107cd in connect () at ../sysdeps/unix/syscall-template.S:84
  11   Thread 0x7f6d15c9a700 (LWP 14484) 0x00007f6d258a27d1 in __GI_ppoll (fds=0x7f6d10000aa0, nfds=5, timeout=<optimized out>, sigmask=0x0)
    at ../sysdeps/unix/sysv/linux/ppoll.c:50
  12   Thread 0x7f6cff7fe700 (LWP 14489) pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
  13   Thread 0x7f6cfffff700 (LWP 14488) 0x00007f6d258a270d in poll () at ../sysdeps/unix/syscall-template.S:84
  14   Thread 0x7f6cfeffd700 (LWP 14490) pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
  15   Thread 0x7f6cfe7fc700 (LWP 14492) 0x00007f6d280107cd in connect () at ../sysdeps/unix/syscall-template.S:84
  16   Thread 0x7f6cfdffb700 (LWP 14493) 0x00007f6d258a27d1 in __GI_ppoll (fds=0x7f6c78012818, nfds=3, timeout=<optimized out>, sigmask=0x0)
    at ../sysdeps/unix/sysv/linux/ppoll.c:50
  17   Thread 0x7f6c93dfe700 (LWP 14498) pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185

enter image description here

Log output:

emulator:Android emulator version 26.0.3.0 (build_id 3965150)
emulator:Found AVD name 'Nexus_5X_API_25'
emulator:Found AVD target architecture: x86_64
emulator:argv[0]: './emulator'; program directory: '/home/sl/opt/android-sdk/tools'
emulator:  Found directory: /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64/

emulator:Probing for /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//kernel-ranchu: file exists
emulator:Auto-config: -engine qemu2 (based on configuration)
emulator:  Found directory: /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64/

emulator:try dir /home/sl/opt/android-sdk/tools
emulator:try dir ./
emulator:try dir ../emulator
emulator:Found target-specific 64-bit emulator binary: /home/sl/opt/android-sdk/tools/../emulator/qemu/linux-x86_64/qemu-system-x86_64
emulator:Adding library search path: '../emulator/lib64'
emulator:Adding library search path: '../emulator/lib64/gles_swiftshader'
emulator:Adding library search path: '../emulator/lib64/gles_angle'
emulator:Adding library search path: '../emulator/lib64/gles_angle9'
emulator:Adding library search path: '../emulator/lib64/gles_angle11'
emulator:Adding library search path: '../emulator/lib64/libstdc++'
emulator: Adding library search path for Qt: '../emulator/lib64/qt/lib'
emulator: Setting Qt plugin search path: QT_QPA_PLATFORM_PLUGIN_PATH=../emulator/lib64/qt/plugins
emulator: Running :/home/sl/opt/android-sdk/tools/../emulator/qemu/linux-x86_64/qemu-system-x86_64
emulator: qemu backend: argv[00] = "/home/sl/opt/android-sdk/tools/../emulator/qemu/linux-x86_64/qemu-system-x86_64"
emulator: qemu backend: argv[01] = "-avd"
emulator: qemu backend: argv[02] = "Nexus_5X_API_25"
emulator: qemu backend: argv[03] = "-verbose"
emulator: Concatenated backend parameters:
 /home/sl/opt/android-sdk/tools/../emulator/qemu/linux-x86_64/qemu-system-x86_64 -avd Nexus_5X_API_25 -verbose
emulator: Android virtual device file at: /home/sl/.android/avd/Nexus_5X_API_25.ini
emulator: virtual device content at /home/sl/.android/avd/Nexus_5X_API_25.avd
emulator: virtual device config file: /home/sl/.android/avd/Nexus_5X_API_25.avd/config.ini
emulator: using core hw config path: /home/sl/.android/avd/Nexus_5X_API_25.avd/hardware-qemu.ini
emulator: using snapshot lock path: /home/sl/.android/avd/Nexus_5X_API_25.avd/snapshot.lock
emulator: Found AVD target API level: 25
emulator: Read property file at /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//build.prop
emulator: No boot.prop property file found.
emulator: Warning: config.ini contains invalid skin.path entry: _no_skin
emulator: autoconfig: -skin 1080x1920
emulator: autoconfig: -skindir (null)
emulator: autoconfig: -kernel /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//kernel-ranchu
emulator: Target arch = 'x86_64'
emulator: Auto-detect: Kernel image requires new device naming scheme.
emulator: Auto-detect: Kernel does not support YAFFS2 partitions.
emulator: autoconfig: -ramdisk /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//ramdisk.img
emulator: Using initial system image: /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//system.img
emulator: No vendor image
emulator: autoconfig: -data /home/sl/.android/avd/Nexus_5X_API_25.avd/userdata-qemu.img
emulator: autoconfig: -initdata /home/sl/.android/avd/Nexus_5X_API_25.avd/userdata.img
emulator: autoconfig: -cache /home/sl/.android/avd/Nexus_5X_API_25.avd/cache.img
emulator: Physical RAM size: 1536MB

emulator: VM heap size 256MB is below hardware specified minimum of 384MB,setting it to that value
emulator: System image is read only
emulator: Found 1 DNS servers: 127.0.1.1
emulator: found magic skin width=1080 height=1920 bpp=16

emulator: CPU Acceleration: working
emulator: CPU Acceleration status: KVM (version 12) is installed and usable.
emulator: GPU emulation enabled using 'host' mode
emulator: Initializing hardware OpenGLES emulation support
emulator: Found 1 DNS servers: 127.0.1.1
Content of hardware configuration file:
  hw.cpu.arch = x86_64
  hw.cpu.ncore = 2
  hw.ramSize = 1536
  hw.screen = multi-touch
  hw.mainKeys = false
  hw.trackBall = false
  hw.keyboard = true
  hw.keyboard.lid = false
  hw.keyboard.charmap = qwerty2
  hw.dPad = false
  hw.rotaryInput = false
  hw.gsmModem = true
  hw.gps = true
  hw.battery = true
  hw.accelerometer = true
  hw.gyroscope = true
  hw.audioInput = true
  hw.audioOutput = true
  hw.sdCard = false
  disk.cachePartition = true
  disk.cachePartition.path = /home/sl/.android/avd/Nexus_5X_API_25.avd/cache.img
  disk.cachePartition.size = 66m
  hw.lcd.width = 1080
  hw.lcd.height = 1920
  hw.lcd.depth = 16
  hw.lcd.density = 420
  hw.lcd.backlight = true
  hw.gpu.enabled = true
  hw.gpu.mode = host
  hw.gpu.blacklisted = no
  hw.initialOrientation = Portrait
  hw.camera.back = none
  hw.camera.front = none
  vm.heapSize = 384
  hw.sensors.light = true
  hw.sensors.pressure = true
  hw.sensors.humidity = true
  hw.sensors.proximity = true
  hw.sensors.magnetic_field = true
  hw.sensors.magnetic_field_uncalibrated = true
  hw.sensors.gyroscope_uncalibrated = true
  hw.sensors.orientation = true
  hw.sensors.temperature = true
  hw.useext4 = true
  hw.arc = false
  hw.arc.autologin = false
  kernel.path = /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//kernel-ranchu
  kernel.newDeviceNaming = yes
  kernel.supportsYaffs2 = no
  disk.ramdisk.path = /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//ramdisk.img
  disk.systemPartition.initPath = /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//system.img
  disk.systemPartition.size = 2765m
  disk.vendorPartition.size = 0
  disk.dataPartition.path = /home/sl/.android/avd/Nexus_5X_API_25.avd/userdata-qemu.img
  disk.dataPartition.size = 800m
  disk.encryptionKeyPartition.path = /home/sl/.android/avd/Nexus_5X_API_25.avd/encryptionkey.img
  PlayStore.enabled = false
  avd.name = Nexus_5X_API_25
  fastboot.forceColdBoot = false
.
QEMU options list:
emulator: argv[00] = "/home/sl/opt/android-sdk/tools/../emulator/qemu/linux-x86_64/qemu-system-x86_64"
emulator: argv[01] = "-dns-server"
emulator: argv[02] = "127.0.1.1"
emulator: argv[03] = "-serial"
emulator: argv[04] = "null"
emulator: argv[05] = "-device"
emulator: argv[06] = "goldfish_pstore,addr=0xff018000,size=0x10000,file=/home/sl/.android/avd/Nexus_5X_API_25.avd/data/misc/pstore/pstore.bin"
emulator: argv[07] = "-cpu"
emulator: argv[08] = "android64"
emulator: argv[09] = "-enable-kvm"
emulator: argv[10] = "-smp"
emulator: argv[11] = "cores=2"
emulator: argv[12] = "-m"
emulator: argv[13] = "1536"
emulator: argv[14] = "-lcd-density"
emulator: argv[15] = "420"
emulator: argv[16] = "-object"
emulator: argv[17] = "iothread,id=disk-iothread"
emulator: argv[18] = "-nodefaults"
emulator: argv[19] = "-kernel"
emulator: argv[20] = "/home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//kernel-ranchu"
emulator: argv[21] = "-initrd"
emulator: argv[22] = "/home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//ramdisk.img"
emulator: argv[23] = "-drive"
emulator: argv[24] = "if=none,index=0,id=system,file=/home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//system.img,read-only"
emulator: argv[25] = "-device"
emulator: argv[26] = "virtio-blk-pci,drive=system,iothread=disk-iothread,modern-pio-notify"
emulator: argv[27] = "-drive"
emulator: argv[28] = "if=none,index=1,id=cache,file=/home/sl/.android/avd/Nexus_5X_API_25.avd/cache.img.qcow2,overlap-check=none,cache=unsafe,l2-cache-size=1048576"
emulator: argv[29] = "-device"
emulator: argv[30] = "virtio-blk-pci,drive=cache,iothread=disk-iothread,modern-pio-notify"
emulator: argv[31] = "-drive"
emulator: argv[32] = "if=none,index=2,id=userdata,file=/home/sl/.android/avd/Nexus_5X_API_25.avd/userdata-qemu.img.qcow2,overlap-check=none,cache=unsafe,l2-cache-size=1048576"
emulator: argv[33] = "-device"
emulator: argv[34] = "virtio-blk-pci,drive=userdata,iothread=disk-iothread,modern-pio-notify"
emulator: argv[35] = "-drive"
emulator: argv[36] = "if=none,index=3,id=encrypt,file=/home/sl/.android/avd/Nexus_5X_API_25.avd/encryptionkey.img.qcow2,overlap-check=none,cache=unsafe,l2-cache-size=1048576"
emulator: argv[37] = "-device"
emulator: argv[38] = "virtio-blk-pci,drive=encrypt,iothread=disk-iothread,modern-pio-notify"
emulator: argv[39] = "-netdev"
emulator: argv[40] = "user,id=mynet"
emulator: argv[41] = "-device"
emulator: argv[42] = "virtio-net-pci,netdev=mynet"
emulator: argv[43] = "-show-cursor"
emulator: argv[44] = "-L"
emulator: argv[45] = "/home/sl/opt/android-sdk/emulator/lib/pc-bios"
emulator: argv[46] = "-soundhw"
emulator: argv[47] = "hda"
emulator: argv[48] = "-vga"
emulator: argv[49] = "none"
emulator: argv[50] = "-append"
emulator: argv[51] = "qemu=1 androidboot.hardware=ranchu clocksource=pit android.qemud=1 console=0 android.checkjni=1 qemu.gles=1 qemu.encrypt=1 qemu.opengles.version=131072 cma=288M qemu.wifi=1 mac80211_hwsim.channels=2 androidboot.android_dt_dir=/sys/bus/platform/devices/ANDR0001:00/properties/android/ ramoops.mem_address=0xff018000 ramoops.mem_size=0x10000 memmap=0x10000$0xff018000"
emulator: argv[52] = "-android-hw"
emulator: argv[53] = "/home/sl/.android/avd/Nexus_5X_API_25.avd/hardware-qemu.ini"
Concatenated QEMU options:
 /home/sl/opt/android-sdk/tools/../emulator/qemu/linux-x86_64/qemu-system-x86_64 -dns-server 127.0.1.1 -serial null -device goldfish_pstore,addr=0xff018000,size=0x10000,file=/home/sl/.android/avd/Nexus_5X_API_25.avd/data/misc/pstore/pstore.bin -cpu android64 -enable-kvm -smp cores=2 -m 1536 -lcd-density 420 -object iothread,id=disk-iothread -nodefaults -kernel /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//kernel-ranchu -initrd /home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//ramdisk.img -drive if=none,index=0,id=system,file=/home/sl/opt/android-sdk/system-images/android-25/google_apis/x86_64//system.img,read-only -device virtio-blk-pci,drive=system,iothread=disk-iothread,modern-pio-notify -drive if=none,index=1,id=cache,file=/home/sl/.android/avd/Nexus_5X_API_25.avd/cache.img.qcow2,overlap-check=none,cache=unsafe,l2-cache-size=1048576 -device virtio-blk-pci,drive=cache,iothread=disk-iothread,modern-pio-notify -drive if=none,index=2,id=userdata,file=/home/sl/.android/avd/Nexus_5X_API_25.avd/userdata-qemu.img.qcow2,overlap-check=none,cache=unsafe,l2-cache-size=1048576 -device virtio-blk-pci,drive=userdata,iothread=disk-iothread,modern-pio-notify -drive if=none,index=3,id=encrypt,file=/home/sl/.android/avd/Nexus_5X_API_25.avd/encryptionkey.img.qcow2,overlap-check=none,cache=unsafe,l2-cache-size=1048576 -device virtio-blk-pci,drive=encrypt,iothread=disk-iothread,modern-pio-notify -netdev user,id=mynet -device virtio-net-pci,netdev=mynet -show-cursor -L /home/sl/opt/android-sdk/emulator/lib/pc-bios -soundhw hda -vga none -append 'qemu=1 androidboot.hardware=ranchu clocksource=pit android.qemud=1 console=0 android.checkjni=1 qemu.gles=1 qemu.encrypt=1 qemu.opengles.version=131072 cma=288M qemu.wifi=1 mac80211_hwsim.channels=2 androidboot.android_dt_dir=/sys/bus/platform/devices/ANDR0001:00/properties/android/ ramoops.mem_address=0xff018000 ramoops.mem_size=0x10000 memmap=0x10000$0xff018000' -android-hw /home/sl/.android/avd/Nexus_5X_API_25.avd/hardware-qemu.ini
emulator: Android qemu version 27.0.2.0 (build_id 4498654) (CL:f388734068bae38c6115263feea33c68eed531fe)

emulator: Starting QEMU main loop
emulator: registered 'boot-properties' qemud service
emulator: Adding boot property: 'ro.opengles.version' = '131072'
emulator: Adding boot property: 'qemu.sf.fake_camera' = 'none'
emulator: Adding boot property: 'dalvik.vm.heapsize' = '384m'
emulator: Adding boot property: 'qemu.hw.mainkeys' = '0'
emulator: Adding boot property: 'qemu.sf.lcd_density' = '420'
emulator: goldfish_events.have-dpad: false
emulator: goldfish_events.have-trackball: false
emulator: goldfish_events.have-camera: false
emulator: goldfish_events.have-keyboard: true
emulator: goldfish_events.have-lidswitch: false
emulator: goldfish_events.have-tabletmode: false
emulator: goldfish_events.have-touch: false
emulator: goldfish_events.have-multitouch: true
emulator: control console listening on port 5554, ADB on port 5555
Not using any http proxy
emulator: android_hw_fingerprint_init: fingerprint qemud listen service initialized




emulator: Warning: config.ini contains invalid skin.path entry: _no_skin
emulator: ERROR: detected a hanging thread 'QEMU2 main loop'. No response for 15000 ms

This is what worked for me:

I have gone to Tools->AVD Manager->Edit(The particular emulator)>Show Advanced Settings

Then in the Emulated Performance section i had the Quick Boot selected, which i changed to Cold Boot and everything started working fine.

Hope this helps.


We were running 27 emulators on a 28 core machine very happily until 1 Dec 2020, when abruptly they started running slowly with a load average 1.5x - 2x worse and these QEMU messages, with occasional days when it returned to normal. Another team also running Android 10 on their emulators also saw the same performance problems on their completely unrelated system. Android 11 and Pie are unaffected.

Our emulator containers are cooked with standard avdmanager-created AVDs and a machine snapshot into docker images, one emulator per image, and we wake up several of these containers.

We still don't entirely understand the cause, but we seem to have solved it by disabling various settings and applications inside the AVD; the snapshot images without these fixes still behave badly. We're not sure which one actually fixed it so I'll list everything here even if it seems unlikely to contribute; if we do determine that, I'll update this answer:

  • 512M sdcard (-c option to avdmanager)
  • pm revoke RECORD_AUDIO for Quicksearch (googlequicksearchbox = Velvet)
  • su root pm disable com.google.android.googlequicksearchbox
  • su root pm disable com.google.android.music
  • Settings > Security > Play protect > disable scan device
  • App Info > Play services > clear storage, clear cache, force stop
  • App Info > Google Auto > Disable
  • Opened maps briefly, skip sign-in, and click 'zoom to location'
  • Normal 'dismiss first time user' stuff like:
    • granting camera permissions, not saving location
    • not sharing any stats or logging in (=No thanks) to Chrome, force-killing it to try to provoke the data-saver screen, and starting Chrome back up.
  • Also, Chrome > Settings > Lite mode > turn on, turn off
    • and tapping in a text window to bring up the keyboard, clearing the 'help build a better keyboard' stuff.
    • Checking data/data/com.google.android.inputmethod.latin/shared_prefs/com.googe.android.inputmethod.latin_preferences.xml for the naughty words - we didn't see the naughty word lists, while we were building the 'let's try this again' image.
  • Accidentally tapped on the quicksearch widget and enabled it; disabled it again.
  • We also a couple of hours doing this - in case it downloaded something before we stopped the emulator and made it take a snapshot.

we still find that Android 10 and Android 11 run 10% slower than Pie, even with these bodges.

Tags:

Qemu

Android Emulator

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