From cb07c9a1864a8eac9f3123e428100d5b2a16e65a Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 14 Nov 2006 02:03:38 -0800 Subject: [PATCH] [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 Cc: Adam Litke Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index bdace87d7c01..2526463c99a7 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -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); -- 2.39.5