bug#32786: (system* ...) call somehow interferes with atomic-box on armv7l

["Михаил Бахтерев" <mob@k.imm.uran.ru>]

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Greetings.

I attach the code sample, which expected behaviour is:

  1. to periodically restart thread, which executes «sleep 1s» with
  system* call;

  2. and then to check if it should repeat the execution.
  
The flag, which controls that re-execution is managed by another thread
through atomic-box primitive.

The code does not run as expected: the sleep executing sleep starts
once, and change seems to remain invisible to main thread.

The code works as expected, when:

  1. (sleep 1) is used instead (system* "sleep" "1s");
  2. running the code on x86_64 cpus.

The use of affinity mask

  taskset 0x01 guile test.scm

does not help.

- MB. Respectfully

P.S. Additional information:

$ guile --version  
guile (GNU Guile) 2.2.4
Copyright (C) 2018 Free Software Foundation, Inc.

License LGPLv3+: GNU LGPL 3 or later <http://gnu.org/licenses/lgpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

$ sh config.guess
armv7l-unknown-linux-gnueabihf

$ pacman -Qi guile 
Name            : guile
Version         : 2.2.4-1
Description     : Portable, embeddable Scheme implementation written in C
Architecture    : armv7h
URL             : https://www.gnu.org/software/guile/
Licenses        : GPL
Groups          : None
Provides        : None
Depends On      : gmp  libltdl  ncurses  texinfo  libunistring  gc  libffi
Optional Deps   : None
Required By     : make
Optional For    : gnutls
Conflicts With  : None
Replaces        : None
Installed Size  : 40.83 MiB
Packager        : Arch Linux ARM Build System <builder+xu9@archlinuxarm.org>
Build Date      : Tue 03 Jul 2018 04:47:53 PM +05
Install Date    : Mon 09 Jul 2018 01:02:48 PM +05
Install Reason  : Installed as a dependency for another package
Install Script  : No
Validated By    : Signature

[-- Attachment #2: test.scm --]
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[-- Attachment #3: cpuinfo --]
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processor	: 0
model name	: ARMv7 Processor rev 10 (v7l)
BogoMIPS	: 7.54
Features	: half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpd32 
CPU implementer	: 0x41
CPU architecture: 7
CPU variant	: 0x2
CPU part	: 0xc09
CPU revision	: 10

processor	: 1
model name	: ARMv7 Processor rev 10 (v7l)
BogoMIPS	: 7.54
Features	: half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpd32 
CPU implementer	: 0x41
CPU architecture: 7
CPU variant	: 0x2
CPU part	: 0xc09
CPU revision	: 10

processor	: 2
model name	: ARMv7 Processor rev 10 (v7l)
BogoMIPS	: 7.54
Features	: half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpd32 
CPU implementer	: 0x41
CPU architecture: 7
CPU variant	: 0x2
CPU part	: 0xc09
CPU revision	: 10

processor	: 3
model name	: ARMv7 Processor rev 10 (v7l)
BogoMIPS	: 7.54
Features	: half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpd32 
CPU implementer	: 0x41
CPU architecture: 7
CPU variant	: 0x2
CPU part	: 0xc09
CPU revision	: 10

Hardware	: Freescale i.MX6 Quad/DualLite (Device Tree)
Revision	: 0000
Serial		: 0000000000000000