The patch titled
swapless page migration: fix fork corruption
has been removed from the -mm tree. Its filename is
swapless-pm-add-r-w-migration-entries-fix-2.patch
This patch was probably dropped from -mm because
it has now been merged into a subsystem tree or
into Linus's tree, or because it was folded into
its parent patch in the -mm tree.
------------------------------------------------------
Subject: swapless page migration: fix fork corruption
From: Hugh Dickins <hugh@xxxxxxxxxxx>
Several times while testing swapless page migration, gcc has tried to exec
a pointer instead of a string: smells like COW mappings are not being
properly write-protected on fork.
The protection in copy_one_pte looks very convincing, until at last you
realize that the second arg to make_migration_entry is a boolean "write",
and SWP_MIGRATION_READ is 30.
Anyway, it's better done like in change_pte_range, using
is_write_migration_entry and make_migration_entry_read.
Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>
Acked-by: Christoph Lameter <clameter@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/memory.c | 9 +++------
1 files changed, 3 insertions(+), 6 deletions(-)
diff -puN mm/memory.c~swapless-pm-add-r-w-migration-entries-fix-2 mm/memory.c
--- 25/mm/memory.c~swapless-pm-add-r-w-migration-entries-fix-2 Fri May 26 13:20:14 2006
+++ 25-akpm/mm/memory.c Fri May 26 13:20:14 2006
@@ -445,16 +445,13 @@ copy_one_pte(struct mm_struct *dst_mm, s
&src_mm->mmlist);
spin_unlock(&mmlist_lock);
}
- if (is_migration_entry(entry) &&
+ if (is_write_migration_entry(entry) &&
is_cow_mapping(vm_flags)) {
- page = migration_entry_to_page(entry);
-
/*
* COW mappings require pages in both parent
- * and child to be set to read.
+ * and child to be set to read.
*/
- entry = make_migration_entry(page,
- SWP_MIGRATION_READ);
+ make_migration_entry_read(&entry);
pte = swp_entry_to_pte(entry);
set_pte_at(src_mm, addr, src_pte, pte);
}
_
Patches currently in -mm which might be from hugh@xxxxxxxxxxx are
mm-vm_bug_on.patch
page-migration-make-do_swap_page-redo-the-fault.patch
migration-remove-unnecessary-pageswapcache-checks.patch
swapless-pm-add-r-w-migration-entries.patch
swapless-pm-add-r-w-migration-entries-fix-2.patch
add-page_mkwrite-vm_operations-method.patch
mm-remove-vm_locked-before-remap_pfn_range-and-drop-vm_shm.patch
swapoff-atomic_inc_not_zero-on-mm_users.patch
remove-unused-o_flags-from-do_shmat.patch
fix-update_mmu_cache-in-fremapc.patch
fix-update_mmu_cache-in-fremapc-fix.patch
page-migration-simplify-migrate_pages.patch
page-migration-simplify-migrate_pages-tweaks.patch
page-migration-handle-freeing-of-pages-in-migrate_pages.patch
page-migration-use-allocator-function-for-migrate_pages.patch
page-migration-support-moving-of-individual-pages.patch
page-migration-detailed-status-for-moving-of-individual-pages.patch
page-migration-support-moving-of-individual-pages-fixes.patch
page-migration-support-a-vma-migration-function.patch
allow-migration-of-mlocked-pages.patch
-
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