[PATCH] MIPS: Fix highmem crash in __update_cache.

From: Lars Persson
Date: Wed Apr 15 2015 - 09:11:17 EST

Due to a change in flush_dcache_page, highmem pages may have the
dcache dirty flag set. Until there is proper support for highmen in
cache.c we must filter out highmem pages to avoid NULL pointer

Signed-off-by: Lars Persson <larper@xxxxxxxx>
arch/mips/mm/cache.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 77d96db..46136f6 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -142,6 +142,10 @@ void __update_cache(struct vm_area_struct *vma, unsigned long address,
if (unlikely(!pfn_valid(pfn)))
page = pfn_to_page(pfn);
+ if (PageHighMem(page))
+ return;
if (page_mapping(page) && Page_dcache_dirty(page)) {
addr = (unsigned long) page_address(page);
if (exec || pages_do_alias(addr, address & PAGE_MASK))

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