tree 62060fb0a274aeb3ca40663d5bd8688140a29753
parent 058a4a534c2392ce6a70ea8372b635de2af1d48f
author Johannes Weiner <hannes@cmpxchg.org> 1481589815 -0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1484217572 +0100

mm: khugepaged: fix radix tree node leak in shmem collapse error path

commit 59749e6ce53735d8b696763742225f126e94603f upstream.

The radix tree counts valid entries in each tree node.  Entries stored
in the tree cannot be removed by simpling storing NULL in the slot or
the internal counters will be off and the node never gets freed again.

When collapsing a shmem page fails, restore the holes that were filled
with radix_tree_insert() with a proper radix tree deletion.

Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages")
Link: http://lkml.kernel.org/r/20161117191138.22769-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <mawilcox@linuxonhyperv.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>