The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>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: [PATCH] s390/mm: make pmdp_invalidate() do invalidation only
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")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.6+
Signed-off-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index dce708e061ea..20e75a2ca93a 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1507,7 +1507,9 @@ static inline pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma,
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_EMPTY));
+ 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