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author | Keir Fraser <keir@xen.org> | 2011-11-30 16:59:58 -0800 |
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committer | Keir Fraser <keir@xen.org> | 2011-11-30 16:59:58 -0800 |
commit | b6cf65cf7aeb21cea11075da268563fca22ede9c (patch) | |
tree | 9c6d177354dedeb4ccdefa3d6523cc993ec5aca2 /xen/common/page_alloc.c | |
parent | a6aed45cf39d2ed4ee7294c08fa0d9d54fcb683e (diff) | |
download | xen-b6cf65cf7aeb21cea11075da268563fca22ede9c.tar.gz xen-b6cf65cf7aeb21cea11075da268563fca22ede9c.tar.bz2 xen-b6cf65cf7aeb21cea11075da268563fca22ede9c.zip |
xenpaging: Fix c/s 23507:0a29c8c3ddf7 ("update machine_to_phys_mapping[] during page deallocation")
This patch clobbers page owner in free_heap_pages() before we are
finished using it. This means that a subsequent test to determine
whether it is safe to avoid safety TLB flushes incorrectly always
determines that it is safe to do so.
The fix is simple: we can defer the original patch's work until after
we are done with the page-owner field.
Thanks to Christian Limpach for spotting this one.
Signed-off-by: Keir Fraser <keir@xen.org>
Diffstat (limited to 'xen/common/page_alloc.c')
-rw-r--r-- | xen/common/page_alloc.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index 3470d32a4a..249bb355dd 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -547,10 +547,6 @@ static void free_heap_pages( for ( i = 0; i < (1 << order); i++ ) { - /* This page is not a guest frame any more. */ - page_set_owner(&pg[i], NULL); /* set_gpfn_from_mfn snoops pg owner */ - set_gpfn_from_mfn(mfn + i, INVALID_M2P_ENTRY); - /* * Cannot assume that count_info == 0, as there are some corner cases * where it isn't the case and yet it isn't a bug: @@ -574,6 +570,10 @@ static void free_heap_pages( pg[i].u.free.need_tlbflush = (page_get_owner(&pg[i]) != NULL); if ( pg[i].u.free.need_tlbflush ) pg[i].tlbflush_timestamp = tlbflush_current_time(); + + /* This page is not a guest frame any more. */ + page_set_owner(&pg[i], NULL); /* set_gpfn_from_mfn snoops pg owner */ + set_gpfn_from_mfn(mfn + i, INVALID_M2P_ENTRY); } avail[node][zone] += 1 << order; |