Commit cb07c9a1 authored Nov 14, 2006 by David Gibson Committed by Linus Torvalds Nov 14, 2006

[PATCH] hugetlb: check for brk() entering a hugepage region



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@gibson.dropbear.id.au>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 68589bc3

mm/mmap.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1880,6 +1880,10 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
		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);

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