This is a note to let you know that I've just added the patch titled
arm64: mm: remove page_mapping check in __sync_icache_dcache
to the 4.6-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:
arm64-mm-remove-page_mapping-check-in-__sync_icache_dcache.patch
and it can be found in the queue-4.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 20c27a4270c775d7ed661491af8ac03264d60fc6 Mon Sep 17 00:00:00 2001
From: Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx>
Date: Tue, 21 Jun 2016 15:32:57 +0800
Subject: arm64: mm: remove page_mapping check in __sync_icache_dcache
From: Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx>
commit 20c27a4270c775d7ed661491af8ac03264d60fc6 upstream.
__sync_icache_dcache unconditionally skips the cache maintenance for
anonymous pages, under the assumption that flushing is only required in
the presence of D-side aliases [see 7249b79f6b4cc ("arm64: Do not flush
the D-cache for anonymous pages")].
Unfortunately, this breaks migration of anonymous pages holding
self-modifying code, where userspace cannot be reasonably expected to
reissue maintenance instructions in response to a migration.
This patch fixes the problem by removing the broken page_mapping(page)
check from the cache syncing code, otherwise we may end up fetching and
executing stale instructions from the PoU.
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/mm/flush.c | 4 ----
1 file changed, 4 deletions(-)
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -71,10 +71,6 @@ void __sync_icache_dcache(pte_t pte, uns
{
struct page *page = pte_page(pte);
- /* no flushing needed for anonymous pages */
- if (!page_mapping(page))
- return;
-
if (!test_and_set_bit(PG_dcache_clean, &page->flags))
sync_icache_aliases(page_address(page),
PAGE_SIZE << compound_order(page));
Patches currently in stable-queue which might be from zhangshaokun@xxxxxxxxxxxxx are
queue-4.6/arm64-mm-remove-page_mapping-check-in-__sync_icache_dcache.patch
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