From: Ralph Campbell <rcampbell@xxxxxxxxxx>
Subject: mm/migrate: add stable check in migrate_vma_insert_page()
migrate_vma_insert_page() closely follows the code in:
__handle_mm_fault()
handle_pte_fault()
do_anonymous_page()
Add a call to check_stable_address_space() after locking the page table
entry before inserting a ZONE_DEVICE private zero page mapping similar to
page faulting a new anonymous page.
Link: http://lkml.kernel.org/r/20200107211208.24595-4-rcampbell@xxxxxxxxxx
Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Cc: Bharata B Rao <bharata@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Chris Down <chris@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
--- a/mm/migrate.c~mm-migrate-add-stable-check-in-migrate_vma_insert_page
+++ a/mm/migrate.c
@@ -48,6 +48,7 @@
#include <linux/page_owner.h>
#include <linux/sched/mm.h>
#include <linux/ptrace.h>
+#include <linux/oom.h>
#include <asm/tlbflush.h>
@@ -2695,6 +2696,14 @@ int migrate_vma_setup(struct migrate_vma
}
EXPORT_SYMBOL(migrate_vma_setup);
+/*
+ * This code closely matches the code in:
+ * __handle_mm_fault()
+ * handle_pte_fault()
+ * do_anonymous_page()
+ * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE
+ * private page.
+ */
static void migrate_vma_insert_page(struct migrate_vma *migrate,
unsigned long addr,
struct page *page,
@@ -2775,6 +2784,9 @@ static void migrate_vma_insert_page(stru
ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
+ if (check_stable_address_space(mm))
+ goto unlock_abort;
+
if (pte_present(*ptep)) {
unsigned long pfn = pte_pfn(*ptep);
_
