Date: Sun, 1 Jun 2008 07:36:59 +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 Message-ID: <200806010737.m517bIff079854@repoman.freebsd.org>
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alc 2008-06-01 07:37:18 UTC
FreeBSD src repository
Modified files:
sys/amd64/amd64 pmap.c
Log:
SVN rev 179471 on 2008-06-01 07:36:59Z by alc
Correct an error in pmap_promote_pde() that may result in an errant
promotion within the kernel's address space. Specifically,
pmap_promote_pde() is only called when the page table page (PTP) that
is referenced by the given PDE has a full "use count", i.e., its
wire_count is 512. Although this guarantees for a user address space
that all 512 PTEs in the PTP hold valid mappings, the same is not true
of the kernel's address space. A kernel PTP always has a use count of
512 regardless of the state of the PTEs. Therefore,
pmap_promote_pde() should not assume (or assert) that the first PTE in
the PTP is valid.
Revision Changes Path
1.619 +3 -5 src/sys/amd64/amd64/pmap.c
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