The patch below does not apply to the 3.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 0c5f83c23ca703d32f930393825487257a5cde6d Mon Sep 17 00:00:00 2001
From: Mel Gorman <mgorman@xxxxxxx>
Date: Wed, 18 Dec 2013 17:08:37 -0800
Subject: [PATCH] mm: numa: do not clear PTE for pte_numa update
The TLB must be flushed if the PTE is updated but change_pte_range is
clearing the PTE while marking PTEs pte_numa without necessarily
flushing the TLB if it reinserts the same entry. Without the flush,
it's conceivable that two processors have different TLBs for the same
virtual address and at the very least it would generate spurious faults.
This patch only unmaps the pages in change_pte_range for a full
protection change.
[riel@xxxxxxxxxx: write pte_numa pte back to the page tables]
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Alex Thorlton <athorlton@xxxxxxx>
Cc: Chegu Vinod <chegu_vinod@xxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 26667971c824..1291a053b167 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -52,17 +52,19 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
pte_t ptent;
bool updated = false;
- ptent = ptep_modify_prot_start(mm, addr, pte);
if (!prot_numa) {
+ ptent = ptep_modify_prot_start(mm, addr, pte);
ptent = pte_modify(ptent, newprot);
updated = true;
} else {
struct page *page;
+ ptent = *pte;
page = vm_normal_page(vma, addr, oldpte);
if (page) {
if (!pte_numa(oldpte)) {
ptent = pte_mknuma(ptent);
+ set_pte_at(mm, addr, pte, ptent);
updated = true;
}
}
@@ -79,7 +81,10 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
if (updated)
pages++;
- ptep_modify_prot_commit(mm, addr, pte, ptent);
+
+ /* Only !prot_numa always clears the pte */
+ if (!prot_numa)
+ ptep_modify_prot_commit(mm, addr, pte, ptent);
} else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) {
swp_entry_t entry = pte_to_swp_entry(oldpte);
--
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