[Qemu-devel] [Bug 1701971] Re: multithreading not working right under qemu user mode for sh4

[Thomas Huth]

A patch for this has apparently been included in QEMU v2.10:
https://git.qemu.org/?p=qemu.git;a=commitdiff;h=4bfa602bc2227f5b5a506a4
Is this issue now completely fixed (so that we can close this ticket), or is 
there something left to do?

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https://bugs.launchpad.net/bugs/1701971

Title:
  multithreading not working right under qemu user mode for sh4

Status in QEMU:
  New

Bug description:
  In a multithreaded program running under qemu-sh4 (version 2.9.0),
  thread termination and/or pthread_join is not working right.

  The attached program works natively on all kinds of platforms, and
  under qemu user mode emulation for at least alpha, armelhf, aarch64,
  powerpc64le.

  How to reproduce:
  - Compile the program: sh4-linux-gnu-gcc-5 -O -Wall -lpthread -o test-tls 
test-tls.c
  - Set environment variables for running qemu-sh4.
  - ~/inst-qemu/2.9.0/bin/qemu-sh4 test-tls

  Expected behaviour: After the "Worker xxxxx dying" line, the main()
  function prints "OK", and the program terminates.

  Actual behaviour (only on sh4): After the "Worker xxxxx dying" line, it 
hangs. Attaching gdb to qemu shows 15 threads with a stack trace like
  #0  safe_syscall_base () at 
/build/qemu-2.9.0/linux-user/host/x86_64/safe-syscall.inc.S:75
  #1  0x00005584f86f4c48 in safe_futex (uaddr=<optimized out>, address@hidden, 
address@hidden, timeout=<optimized out>, address@hidden, 
      address@hidden) at /build/qemu-2.9.0/linux-user/syscall.c:921
  #2  0x00005584f870353b in do_futex (val3=-161181992, uaddr2=4134624624, 
timeout=0, val=<optimized out>, op=<optimized out>, uaddr=<optimized out>)
      at /build/qemu-2.9.0/linux-user/syscall.c:7147
  #3  do_syscall (cpu_env=<optimized out>, num=240, arg1=<optimized out>, 
arg2=<optimized out>, arg3=<optimized out>, arg4=0, arg5=-160342672, 
      arg6=-161181992, arg7=0, arg8=0) at 
/build/qemu-2.9.0/linux-user/syscall.c:11692
  #4  0x00005584f86f454a in cpu_loop (address@hidden) at 
/build/qemu-2.9.0/linux-user/main.c:2676
  #5  0x00005584f86f5dd5 in clone_func (arg=0x7fff4d485c20) at 
/build/qemu-2.9.0/linux-user/syscall.c:6234
  #6  0x00007f08f05a46ba in start_thread (arg=0x7f08f1368700) at 
pthread_create.c:333
  #7  0x00007f08f02da3dd in clone () at 
../sysdeps/unix/sysv/linux/x86_64/clone.S:109

  and 1 thread with a stack trace like
  #0  safe_syscall_base () at 
/build/qemu-2.9.0/linux-user/host/x86_64/safe-syscall.inc.S:75
  #1  0x00005584f86f4c48 in safe_futex (uaddr=<optimized out>, address@hidden, 
address@hidden, timeout=<optimized out>, address@hidden, 
      address@hidden) at /build/qemu-2.9.0/linux-user/syscall.c:921
  #2  0x00005584f870353b in do_futex (val3=-161180376, uaddr2=4135101768, 
timeout=0, val=<optimized out>, op=<optimized out>, uaddr=<optimized out>)
      at /build/qemu-2.9.0/linux-user/syscall.c:7147
  #3  do_syscall (cpu_env=<optimized out>, num=240, arg1=<optimized out>, 
arg2=<optimized out>, arg3=<optimized out>, arg4=0, arg5=-159865528, 
      arg6=-161180376, arg7=0, arg8=0) at 
/build/qemu-2.9.0/linux-user/syscall.c:11692
  #4  0x00005584f86f454a in cpu_loop (env=0x5584fb3b99a8) at 
/build/qemu-2.9.0/linux-user/main.c:2676
  #5  0x00005584f86c12d3 in main (argc=<optimized out>, argv=0x7fff4d4878b8, 
envp=<optimized out>)
      at /build/qemu-2.9.0/linux-user/main.c:4860

  and 1 thread with a stack trace like
  #0  syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
  #1  0x00005584f876eab5 in qemu_futex_wait (val=<optimized out>, f=<optimized 
out>) at /build/qemu-2.9.0/include/qemu/futex.h:26
  #2  qemu_event_wait (address@hidden <rcu_call_ready_event>) at 
/build/qemu-2.9.0/util/qemu-thread-posix.c:399
  #3  0x00005584f87748ce in call_rcu_thread (opaque=<optimized out>) at 
/build/qemu-2.9.0/util/rcu.c:249
  #4  0x00007f08f05a46ba in start_thread (arg=0x7f08eff62700) at 
pthread_create.c:333
  #5  0x00007f08f02da3dd in clone () at 
../sysdeps/unix/sysv/linux/x86_64/clone.S:109

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