[Xen-changelog] [xen stable-4.9] x86: don't wrongly trigger linear page table assertion (2)

[patchbot@xxxxxxx]

commit d1cca0780b42c864ce1e83632d506e2af89d0356
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Dec 12 14:37:29 2017 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Dec 12 14:37:29 2017 +0100

    x86: don't wrongly trigger linear page table assertion (2)
    
    _put_final_page_type(), when free_page_type() has exited early to allow
    for preemption, should not update the time stamp, as the page continues
    to retain the typ which is in the process of being unvalidated. I can't
    see why the time stamp update was put on that path in the first place
    (albeit it may well have been me who had put it there years ago).
    
    This is part of XSA-240.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Tested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: George Dunlap <george.dunlap.com>
    master commit: e40b0219a8c77741ae48989efb520f4a762a5be3
    master date: 2017-12-12 14:27:34 +0100
---
 xen/arch/x86/mm.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index e77574f..4b77d02 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -2594,9 +2594,6 @@ static int _put_final_page_type(struct page_info *page, 
unsigned long type,
     {
         ASSERT((page->u.inuse.type_info &
                 (PGT_count_mask|PGT_validated|PGT_partial)) == 1);
-        if ( !(shadow_mode_enabled(page_get_owner(page)) &&
-               (page->count_info & PGC_page_table)) )
-            page_set_tlbflush_timestamp(page);
         wmb();
         page->u.inuse.type_info |= PGT_validated;
     }
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.9

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