CVS commit: src/sys/arch/m68k/m68k

["Jason R Thorpe" <thorpej%netbsd.org@localhost>]

Module Name:    src
Committed By:   thorpej
Date:           Thu May  7 15:33:41 UTC 2026

Modified Files:
        src/sys/arch/m68k/m68k: pmap_68k.c

Log Message:
Fix return value logic in pmap_changebit() (used to implement
pmap_clear_reference() and pmap_clear_modify()): We need to seed
the "combined_pte" with the mod/ref information stashed in the
vm_page because all of the mappings to the page may have already
been removed via pmap_page_protect(..., UVM_PROT_NONE), and we
need to use that "combined_pte" to return true if any of the bits
we've been asked to clear were set (previously we only returned
true if we actually cleared one from a mapping's PTE, which,
as previously noted, might all be gone by this point).

The symptom here would be random crashes under memory pressure,
things like spurious NULL-derefs, indicative of an anonymous
page being tossed under memory pressure and re-ZFOD'd, rather
than being sent to swap and properly paged back in.


To generate a diff of this commit:
cvs rdiff -u -r1.65 -r1.66 src/sys/arch/m68k/m68k/pmap_68k.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.