Date: Tue, 27 Jun 2006 04:28:23 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/amd64/amd64 pmap.c src/sys/i386/i386 pmap.c Message-ID: <200606270428.k5R4SN46076322@repoman.freebsd.org>
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alc 2006-06-27 04:28:23 UTC
FreeBSD src repository
Modified files:
sys/amd64/amd64 pmap.c
sys/i386/i386 pmap.c
Log:
Correct a very old and very obscure bug: vmspace_fork() calls
pmap_copy() if the mapping is VM_INHERIT_SHARE. Suppose the mapping
is also wired. vmspace_fork() clears the wiring attributes in the vm
map entry but pmap_copy() copies the PG_W attribute in the PTE. I
don't think this is catastrophic. It blocks pmap_remove_pages() from
destroying the mapping and corrupts the pmap's wiring count.
This revision fixes the problem by changing pmap_copy() to clear the
PG_W attribute.
Reviewed by: tegge@
Revision Changes Path
1.560 +4 -3 src/sys/amd64/amd64/pmap.c
1.564 +5 -3 src/sys/i386/i386/pmap.c
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