This is a note to let you know that I've just added the patch titled
x86, mm: fix gup_pte_range() vs DAX mappings
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-mm-fix-gup_pte_range-vs-dax-mappings.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ef947b2529f918d9606533eb9c32b187ed6a5ede Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Date: Thu, 9 Mar 2017 16:16:42 -0800
Subject: x86, mm: fix gup_pte_range() vs DAX mappings
From: Dan Williams <dan.j.williams@xxxxxxxxx>
commit ef947b2529f918d9606533eb9c32b187ed6a5ede upstream.
gup_pte_range() fails to check pte_allows_gup() before translating a DAX
pte entry, pte_devmap(), to a page. This allows writes to read-only
mappings, and bypasses the DAX cacheline dirty tracking due to missed
'mkwrite' faults. The gup_huge_pmd() path and the gup_huge_pud() path
correctly check pte_allows_gup() before checking for _devmap() entries.
Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings")
Link: http://lkml.kernel.org/r/148804251312.36605.12665024794196605053.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reported-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reported-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Xiong Zhou <xzhou@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/mm/gup.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -120,6 +120,11 @@ static noinline int gup_pte_range(pmd_t
return 0;
}
+ if (!pte_allows_gup(pte_val(pte), write)) {
+ pte_unmap(ptep);
+ return 0;
+ }
+
if (pte_devmap(pte)) {
pgmap = get_dev_pagemap(pte_pfn(pte), pgmap);
if (unlikely(!pgmap)) {
@@ -127,8 +132,7 @@ static noinline int gup_pte_range(pmd_t
pte_unmap(ptep);
return 0;
}
- } else if (!pte_allows_gup(pte_val(pte), write) ||
- pte_special(pte)) {
+ } else if (pte_special(pte)) {
pte_unmap(ptep);
return 0;
}
Patches currently in stable-queue which might be from dan.j.williams@xxxxxxxxx are
queue-4.9/nfit-libnvdimm-fix-interleave-set-cookie-calculation.patch
queue-4.9/x86-mm-fix-gup_pte_range-vs-dax-mappings.patch