From 9aed8614af5a05cdaa32a0b78b0f1a424754a958 Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Wed, 6 Aug 2014 16:07:05 -0700 Subject: [PATCH] mm/memory.c: don't forget to set softdirty on file mapped fault Otherwise we may not notice that pte was softdirty because pte_mksoft_dirty helper _returns_ new pte but doesn't modify the argument. In case if page fault happend on dirty filemapping the newly created pte may loose softdirty bit thus if a userspace program is tracking memory changes with help of a memory tracker (CONFIG_MEM_SOFT_DIRTY) it might miss modification of a memory page (which in worts case may lead to data inconsistency). Signed-off-by: Cyrill Gorcunov Acked-by: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memory.c b/mm/memory.c index 01d0289f30a7..7e131325bdf8 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2744,7 +2744,7 @@ void do_set_pte(struct vm_area_struct *vma, unsigned long address, if (write) entry = maybe_mkwrite(pte_mkdirty(entry), vma); else if (pte_file(*pte) && pte_file_soft_dirty(*pte)) - pte_mksoft_dirty(entry); + entry = pte_mksoft_dirty(entry); if (anon) { inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); page_add_new_anon_rmap(page, vma, address); -- 2.20.1