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

[Thomas Huth]

This is an automated cleanup. This bug report has been moved to QEMU's
new bug tracker on gitlab.com and thus gets marked as 'expired' now.
Please continue with the discussion here:

 https://gitlab.com/qemu-project/qemu/-/issues/509


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

** Bug watch added: gitlab.com/qemu-project/qemu/-/issues #509
   https://gitlab.com/qemu-project/qemu/-/issues/509

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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:
  Expired

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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