[Xen-changelog] [xen stable-4.6] x86: don't wrongly trigger linear page table assertion (2)

[patchbot@xxxxxxx]

commit 6e43623e923f3fc79e56a23ea669d7d07ce46e39
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Dec 12 15:07:17 2017 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Dec 12 15:07:17 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 189ea17..a79a0ab 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -2445,9 +2445,6 @@ 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-4.6

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