bash.exe -c "nohup winver.exe &" leaves init using 100% CPU on one core

[dreamlayers]

Windows Version

Microsoft Windows [Version 10.0.19045.5131]

WSL Version

2.1.4.0

Are you using WSL 1 or WSL 2?

• WSL 2
• WSL 1

Kernel Version

4.4.0-19041-Microsoft

Distro Version

Ubuntu 24.04.1 LTS

Other Software

No response

Repro Steps

If I open an ordinary Windows cmd prompt window (not WSL). There run bash.exe -c "nohup winver.exe &" or wsl.exe -e bash -c "nohup winver.exe &".

Expected Behavior

WSL should run temporarily, starting winver.exe and then closing.

Actual Behavior

After WSL exits, an init process remains, using 100% CPU on one core. Even after winver.exe is closed, that init process remains, endlessly wasting CPU time like that. Every time this is repeated, another init process like this is created, each wasting CPU time.

Other than this, everything seems fine. I am returned to the cmd prompt immediately, and winver remains running.

If the nohup is not used, or the & is not used, then this problem does not occur.

Workaround: Using bash.exe -c "winver.exe &" gives more reasonable behaviour. The first run leaves behind two init processes, but they do not waste CPU time, and repeating it does not create more lingering init processes. Even though nohup is not used, winver remains running, probably because SIGHUP doesn't affect ordinary Windows processes. Another alternative that doesn't cause problems is bash.exe -c "winver.exe & disown"

Diagnostic Logs

No response

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View similar issues

Please view the issues below to see if they solve your problem, and if the issue describes your problem please consider closing this one and thumbs upping the other issue to help us prioritize it!

Closed similar issues:

• init loops with SIGSEGV (#7901), similarity score: 0.72
• High CPU utilization for Microsoft Bash Launcher when session is idle (#8008), similarity score: 0.71
• WSL 2: Cannot launch detached/immune to hangups (nohup ... &) processes from wsl-command (#5143), similarity score: 0.70

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[OneBlue]

Thank you @dreamlayers. Interestingly I can't reproduce the issue. Could you share a coredump of the init process that's consuming CPU ?

[dreamlayers]

Here is a core dump generated via gcore from WSL1: hanging_init_core.gz.

This was soon after booting into Windows. The first time I did bash.exe -c "nohup winver.exe &", winver didn't run at all, and init wasn't consuming CPU afterwards. I waited for CPU activity to fall to single digits and then tried again and reproduced this. It seems like there is some race condition when running an ordinary Windows program from WSL1 and then immediately exiting WSL1. When launching Windows programs that take a longer time to start up, I need a sleep 1 after the & to make them start successfully.