From: David Gibson Date: Sun, 28 Oct 2007 21:20:34 +0000 (+0100) Subject: hugetlb: check for brk() entering a hugepage region X-Git-Tag: v2.6.16.56-rc2~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6a93b22bc8569315b2e0ce07297b73673882925a;p=thirdparty%2Fkernel%2Fstable.git 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 Signed-off-by: Adrian Bunk --- diff --git a/mm/mmap.c b/mm/mmap.c index f2ac461a357e7..a04576de32546 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1870,6 +1870,10 @@ 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);