This is a note to let you know that I've just added the patch titled
s390/mm: make pmdp_invalidate() do invalidation only
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:
s390-mm-make-pmdp_invalidate-do-invalidation-only.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 91c575b335766effa6103eba42a82aea560c365f Mon Sep 17 00:00:00 2001
From: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Date: Mon, 18 Sep 2017 16:10:35 +0200
Subject: s390/mm: make pmdp_invalidate() do invalidation only
From: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
commit 91c575b335766effa6103eba42a82aea560c365f upstream.
Commit 227be799c39a ("s390/mm: uninline pmdp_xxx functions from pgtable.h")
inadvertently changed the behavior of pmdp_invalidate(), so that it now
clears the pmd instead of just marking it as invalid. Fix this by restoring
the original behavior.
A possible impact of the misbehaving pmdp_invalidate() would be the
MADV_DONTNEED races (see commits ced10803 and 58ceeb6b), although we
should not have any negative impact on the related dirty/young flags,
since those flags are not set by the hardware on s390.
Fixes: 227be799c39a ("s390/mm: uninline pmdp_xxx functions from pgtable.h")
Signed-off-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/include/asm/pgtable.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1359,7 +1359,9 @@ static inline pmd_t pmdp_huge_clear_flus
static inline void pmdp_invalidate(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmdp)
{
- pmdp_xchg_direct(vma->vm_mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_INVALID));
+ pmd_t pmd = __pmd(pmd_val(*pmdp) | _SEGMENT_ENTRY_INVALID);
+
+ pmdp_xchg_direct(vma->vm_mm, addr, pmdp, pmd);
}
#define __HAVE_ARCH_PMDP_SET_WRPROTECT
Patches currently in stable-queue which might be from gerald.schaefer@xxxxxxxxxx are
queue-4.9/s390-mm-make-pmdp_invalidate-do-invalidation-only.patch