Comment 0 for bug 1957188

Brief Description
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Since commit https://review.opendev.org/plugins/gitiles/starlingx/kernel/+/7b55e47e1d9fe9524b6b6b56cb6cb6efa11938ec the kernel's kthread_cpus= argument parser utilizes a lot of stack space, which may or may not be harmful. This was discovered when building the kernel with the following options:

      CONFIG_MAXSMP=y
      CONFIG_NR_CPUS=8192
      CONFIG_CPUMASK_OFFSTACK=y
      CONFIG_FRAME_WARN=1024

which results in the following compilation-time warning:

        CC kernel/cpu.o
      kernel/cpu.c: In function 'kthread_setup':
      kernel/cpu.c:2475:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]

Severity
--------
Minor: I am assuming that the warning is not critical, as we have not observed misbehaviour with the kthread_cpus argument, but I would like to fix the issue regardless.

Steps to Reproduce
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Please see above for the build configuration that reproduces the warning.

Expected Behavior
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No kernel build warnings

Actual Behavior
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Kernel build warning about kthread_setup function's frame size exceeding 1KiB.

Reproducibility
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100%

System Configuration
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Not applicable.

Branch/Pull Time/Commit
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The issue is reproduced since the merge of the commit at https://review.opendev.org/plugins/gitiles/starlingx/kernel/+/7b55e47e1d9fe9524b6b6b56cb6cb6efa11938ec

Last Pass
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Not applicable.

Timestamp/Logs
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Please see the issue description.

Test Activity
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Exploratory developer testing

Workaround
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None.