[Bug 1908626] Re: Atomic test-and-set instruction does not work on qemu-user

[taos]

** Changed in: qemu
       Status: Expired => New

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https://bugs.launchpad.net/bugs/1908626

Title:
  Atomic test-and-set instruction does not work on qemu-user

Status in QEMU:
  New

Bug description:
  I try to compile and run PostgreSQL/Greenplum database inside docker 
container/qemu-aarch64-static:
  ```
   host: CentOS7 x86_64
   container: centos:centos7.9.2009 --platform linux/arm64/v8
   qemu-user-static: https://github.com/multiarch/qemu-user-static/releases/
  ```

  However, GP/PG's spinlock always gets stuck and reports PANIC errors. It 
seems its spinlock
  has something wrong.
  ```
  https://github.com/greenplum-db/gpdb/blob/master/src/include/storage/s_lock.h
  
https://github.com/greenplum-db/gpdb/blob/master/src/backend/storage/lmgr/s_lock.c
  ```

  So I extract its spinlock implementation into one test C source file (see 
attachment file),
  and get reprodcued:

  ```
  $ gcc spinlock_qemu.c
  $ ./a.out 
  C -- slock inited, lock value is: 0
  parent 139642, child 139645
  P -- slock lock before, lock value is: 0
  P -- slock locked, lock value is: 1
  P -- slock unlock after, lock value is: 0
  C -- slock lock before, lock value is: 1
  P -- slock lock before, lock value is: 1
  C -- slock locked, lock value is: 1
  C -- slock unlock after, lock value is: 0
  C -- slock lock before, lock value is: 1
  P -- slock locked, lock value is: 1
  P -- slock unlock after, lock value is: 0
  P -- slock lock before, lock value is: 1
  C -- slock locked, lock value is: 1
  C -- slock unlock after, lock value is: 0
  P -- slock locked, lock value is: 1
  C -- slock lock before, lock value is: 1
  P -- slock unlock after, lock value is: 0
  C -- slock locked, lock value is: 1
  P -- slock lock before, lock value is: 1
  C -- slock unlock after, lock value is: 0
  P -- slock locked, lock value is: 1
  C -- slock lock before, lock value is: 1
  P -- slock unlock after, lock value is: 0
  C -- slock locked, lock value is: 1
  P -- slock lock before, lock value is: 1
  C -- slock unlock after, lock value is: 0
  P -- slock locked, lock value is: 1
  C -- slock lock before, lock value is: 1
  P -- slock unlock after, lock value is: 0
  P -- slock lock before, lock value is: 1
  spin timeout, lock value is 1 (pid 139642)
  spin timeout, lock value is 1 (pid 139645)
  spin timeout, lock value is 1 (pid 139645)
  spin timeout, lock value is 1 (pid 139642)
  spin timeout, lock value is 1 (pid 139645)
  spin timeout, lock value is 1 (pid 139642)
  ...
  ...
  ...
  ```

  NOTE: this code always works on PHYSICAL ARM64 server.

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