The patch titled
hugetlb: check for brk() entering a hugepage region
has been added to the -mm tree. Its filename is
hugetlb-check-for-brk-entering-a-hugepage-region.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: hugetlb: check for brk() entering a hugepage region
From: "'David Gibson'" <david@xxxxxxxxxxxxxxxxxxxxx>
Unlike mmap(), the codepath for brk() creates a vma without first checking
that it doesn't touch a region exclusively reserved for hugepages. On
powerpc, this can allow it to create a normal page vma in a hugepage
region, causing oopses and other badness.
Add a test to prevent this. With this patch, brk() will simply fail if it
attempts to move the break into a hugepage reserved region.
Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
Cc: Adam Litke <agl@xxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/mmap.c | 4 ++++
1 file changed, 4 insertions(+)
diff -puN mm/mmap.c~hugetlb-check-for-brk-entering-a-hugepage-region mm/mmap.c
--- a/mm/mmap.c~hugetlb-check-for-brk-entering-a-hugepage-region
+++ a/mm/mmap.c
@@ -1880,6 +1880,10 @@ unsigned long do_brk(unsigned long addr,
if ((addr + len) > TASK_SIZE || (addr + len) < addr)
return -EINVAL;
+ error = is_hugepage_only_range(current->mm, addr, len);
+ if (error)
+ return error;
+
flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
error = arch_mmap_check(addr, len, flags);
_
Patches currently in -mm which might be from david@xxxxxxxxxxxxxxxxxxxxx are
hugetlb-prepare_hugepage_range-check-offset-too.patch
hugetlb-check-for-brk-entering-a-hugepage-region.patch
git-powerpc.patch
__unmap_hugepage_range-add-comment.patch
shared-page-table-for-hugetlb-page-v4.patch
htlb-forget-rss-with-pt-sharing.patch
-
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