[Qemu-devel] [Bug 1805256] Re: qemu-img hangs on high core count ARM system

[贞贵李]

Hi, I also found a problem that qemu-img convert hands in ARM.

The convert command line is "qemu-img convert -f qcow2 -O raw disk.qcow2
disk.raw ".

The bt is below:

Thread 2 (Thread 0x40000b776e50 (LWP 27215)):
#0 0x000040000a3f2994 in sigtimedwait () from /lib64/libc.so.6
#1 0x000040000a39c60c in sigwait () from /lib64/libpthread.so.0
#2 0x0000aaaaaae82610 in sigwait_compat (opaque=0xaaaac5163b00) at 
util/compatfd.c:37
#3 0x0000aaaaaae85038 in qemu_thread_start (address@hidden) at 
util/qemu_thread_posix.c:496
#4 0x000040000a3918bc in start_thread () from /lib64/libpthread.so.0
#5 0x000040000a492b2c in thread_start () from /lib64/libc.so.6

Thread 1 (Thread 0x40000b573370 (LWP 27214)):
#0 0x000040000a489020 in ppoll () from /lib64/libc.so.6
#1 0x0000aaaaaadaefc0 in ppoll (__ss=0x0, __timeout=0x0, __nfds=<optimized 
out>, __fds=<optimized out>) at /usr/include/bits/poll2.h:77
#2 qemu_poll_ns (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized 
out>) at qemu_timer.c:391
#3 0x0000aaaaaadae014 in os_host_main_loop_wait (timeout=<optimized out>) at 
main_loop.c:272
#4 0x0000aaaaaadae190 in main_loop_wait (nonblocking=<optimized out>) at 
main_loop.c:534
#5 0x0000aaaaaad97be0 in convert_do_copy (s=0xffffdc32eb48) at qemu-img.c:1923
#6 0x0000aaaaaada2d70 in img_convert (argc=<optimized out>, argv=<optimized 
out>) at qemu-img.c:2414
#7 0x0000aaaaaad99ac4 in main (argc=7, argv=<optimized out>) at qemu-img.c:5305


Do you find the cause of the problem and fix it? Thanks for your reply!

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https://bugs.launchpad.net/bugs/1805256

Title:
  qemu-img hangs on high core count ARM system

Status in QEMU:
  New

Bug description:
  On the HiSilicon D06 system - a 96 core NUMA arm64 box - qemu-img
  frequently hangs (~50% of the time) with this command:

  qemu-img convert -f qcow2 -O qcow2 /tmp/cloudimg /tmp/cloudimg2

  Where "cloudimg" is a standard qcow2 Ubuntu cloud image. This
  qcow2->qcow2 conversion happens to be something uvtool does every time
  it fetches images.

  Once hung, attaching gdb gives the following backtrace:

  (gdb) bt
  #0  0x0000ffffae4f8154 in __GI_ppoll (fds=0xaaaae8a67dc0, 
nfds=187650274213760, 
      timeout=<optimized out>, address@hidden, sigmask=0xffffc123b950)
      at ../sysdeps/unix/sysv/linux/ppoll.c:39
  #1  0x0000aaaabbefaf00 in ppoll (__ss=0x0, __timeout=0x0, __nfds=<optimized 
out>, 
      __fds=<optimized out>) at /usr/include/aarch64-linux-gnu/bits/poll2.h:77
  #2  qemu_poll_ns (fds=<optimized out>, nfds=<optimized out>, 
      address@hidden) at util/qemu-timer.c:322
  #3  0x0000aaaabbefbf80 in os_host_main_loop_wait (timeout=-1)
      at util/main-loop.c:233
  #4  main_loop_wait (nonblocking=<optimized out>) at util/main-loop.c:497
  #5  0x0000aaaabbe2aa30 in convert_do_copy (s=0xffffc123bb58) at 
qemu-img.c:1980
  #6  img_convert (argc=<optimized out>, argv=<optimized out>) at 
qemu-img.c:2456
  #7  0x0000aaaabbe2333c in main (argc=7, argv=<optimized out>) at 
qemu-img.c:4975

  Reproduced w/ latest QEMU git (@ 53744e0a182)

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