vm_phys: Check for overlap when adding a segment
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Authored by olce on Jan 23 2025, 5:15 PM.

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markj
dougm
alc

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rG8a14ddcc1d8e: vm_phys: Check for overlap when adding a segment

Summary

Segments are passed by machine-dependent routines, so explicit checks
will make debugging much easier on very weird machines or when someone
is tweaking these machine-dependent routines. Additionally, this
operation is not performance-sensitive.

For the same reasons, test that we don't reach the maximum number of
physical segments (the compile-time of the internal storage) in
production kernel (replaces the existing KASSERT()).

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Repository

rG FreeBSD src repository

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Event Timeline

olce created this revision.Jan 23 2025, 5:15 PM

Herald added a subscriber: imp. · View Herald TranscriptJan 23 2025, 5:15 PM

olce requested review of this revision.Jan 23 2025, 5:15 PM

Harbormaster completed remote builds in B61927: Diff 149784.Jan 23 2025, 5:15 PM

olce added a parent revision: D48627: vm_phys_add_seg(): Check for bad segments, allow empty ones.Jan 23 2025, 5:21 PM

olce added a child revision: D48629: vm_phys_avail_count(): Fix out-of-bounds accesses.

markj added inline comments.Jan 24 2025, 2:46 PM

sys/vm/vm_phys.c
424–430	Why is this an assertion when the other check applies to non-INVARIANTS kernels?
441	Stray semicolon at the end of the message?

Cater to comments.

sys/vm/vm_phys.c
424–430	Nothing strong, I just felt less compelled to convert this check to a regular test+panic as the number of domains is registered once by machine-dependent code and then passed domains are either 0 or some index from a loop using `vm_ndomains` as bound. Changed to a true panic.