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authorWill Deacon <will.deacon@arm.com>2012-11-16 14:15:00 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-11 12:04:22 -0700
commit4db251fa782d61a3603414cced4361ff732dc119 (patch)
treef96a3cf8dfc7c7075147f598cfbfc107adf8e1af
parent85faa17c6abc754dac48a82f3d9bc70dd1c7453b (diff)
downloadlinux-linaro-stable-4db251fa782d61a3603414cced4361ff732dc119.tar.gz
mm: highmem: don't treat PKMAP_ADDR(LAST_PKMAP) as a highmem address
commit 498c2280212327858e521e9d21345d4cc2637f54 upstream. kmap_to_page returns the corresponding struct page for a virtual address of an arbitrary mapping. This works by checking whether the address falls in the pkmap region and using the pkmap page tables instead of the linear mapping if appropriate. Unfortunately, the bounds checking means that PKMAP_ADDR(LAST_PKMAP) is incorrectly treated as a highmem address and we can end up walking off the end of pkmap_page_table and subsequently passing junk to pte_page. This patch fixes the bound check to stay within the pkmap tables. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/highmem.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/highmem.c b/mm/highmem.c
index 2a07f97dabf1..09fc744d104e 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -98,7 +98,7 @@ struct page *kmap_to_page(void *vaddr)
{
unsigned long addr = (unsigned long)vaddr;
- if (addr >= PKMAP_ADDR(0) && addr <= PKMAP_ADDR(LAST_PKMAP)) {
+ if (addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP)) {
int i = (addr - PKMAP_ADDR(0)) >> PAGE_SHIFT;
return pte_page(pkmap_page_table[i]);
}