[PATCH] pnfs-block: removing DM device maybe cause oops when call dev_remove

[fanchaoting <fanchaoting@cn.fujitsu.com>]

when pnfs block using device mapper,if umounting later,it maybe
cause oops. we apply "1 + sizeof(bl_umount_request)" memory for
msg->data, the memory maybe overflow when we do "memcpy(&dataptr
[sizeof(bl_msg)], &bl_umount_request, sizeof(bl_umount_request))",
because the size of bl_msg is more than 1 byte.

   Signed-off-by: fanchaoting<fanchaoting@cn.fujitsu.com>

---
 fs/nfs/blocklayout/blocklayoutdm.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/nfs/blocklayout/blocklayoutdm.c b/fs/nfs/blocklayout/blocklayoutdm.c
index 737d839..8df9afa 100644
--- a/fs/nfs/blocklayout/blocklayoutdm.c
+++ b/fs/nfs/blocklayout/blocklayoutdm.c
@@ -55,7 +55,7 @@ static void dev_remove(struct net *net, dev_t dev)

        bl_pipe_msg.bl_wq = &nn->bl_wq;
        memset(msg, 0, sizeof(*msg));
-       msg->data = kzalloc(1 + sizeof(bl_umount_request), GFP_NOFS);
+       msg->data = kzalloc(sizeof(bl_msg) + sizeof(bl_umount_request), GFP_NOFS);
        if (!msg->data)
                goto out;

--
1.7.1