#1126509 flightgear: fgfs freezes for minutes on exit waiting for FUTEX

Package:
flightgear
Source:
flightgear
Description:
Flight Gear Flight Simulator
Submitter:
Date:
2026-01-27 19:03:07 UTC
Severity:
normal
#1126509#5
Date:
2026-01-27 19:02:19 UTC
From:
To:
Dear Maintainer,

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After upgrade to 2024, fgfs often (but not every single time) stays
frozen when I exit, sometimes over 5 minutes. This never happened with
the earlier 2020 fgfs.

Strace shows it is blocked waiting for a FUTEX rather than using CPU or
disk.

=> strace -p 3681126
strace: Process 3681126 attached
futex(0x7f544f7fe990, FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, 3681243, NULL, FUTEX_BITSET_MATCH_ANY^Cstrace: Process 3681126 detached
 <detached ...>

This happens regardless of the multithreading options chosen, normally use:
   --prop:/sim/rendering/multithreading-mode=CullThreadPerCameraDrawThreadPerContext"

There's no real work-around for this issue as it would be better not
issue a SIGKILL and interrupt possible saving of files.
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