Date: Wed, 27 Sep 2006 18:10:16 +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: <200609271810.k8RIAGSu022079@repoman.freebsd.org>
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alc 2006-09-27 18:10:16 UTC
FreeBSD src repository
Modified files: (Branch: RELENG_6)
sys/amd64/amd64 pmap.c
sys/i386/i386 pmap.c
Log:
MFC
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.
Approved by: re (mux)
Revision Changes Path
1.516.2.8 +4 -3 src/sys/amd64/amd64/pmap.c
1.523.2.8 +5 -3 src/sys/i386/i386/pmap.c
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