tree 7b0036807c892d29f06f802de1a835b68a21b89b
parent 7a5091d58419b4e5222abce58a40c072786ea1d6
author Anthony Iliopoulos <anthony.iliopoulos@huawei.com> 1400059788 +0200
committer H. Peter Anvin <hpa@linux.intel.com> 1400024049 -0700

x86, mm, hugetlb: Add missing TLB page invalidation for hugetlb_cow()

The invalidation is required in order to maintain proper semantics
under CoW conditions. In scenarios where a process clones several
threads, a thread operating on a core whose DTLB entry for a
particular hugepage has not been invalidated, will be reading from
the hugepage that belongs to the forked child process, even after
hugetlb_cow().

The thread will not see the updated page as long as the stale DTLB
entry remains cached, the thread attempts to write into the page,
the child process exits, or the thread gets migrated to a different
processor.

Signed-off-by: Anthony Iliopoulos <anthony.iliopoulos@huawei.com>
Link: http://lkml.kernel.org/r/20140514092948.GA17391@server-36.huawei.corp
Suggested-by: Shay Goikhman <shay.goikhman@huawei.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> # v2.6.16+ (!)