NLM: don't use CLONE_SIGHAND in nlmclnt_recovery

reclaimer() calls allow_signal() which plays with parent process's ->sighand.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/lockd/clntlock.c

@@ -153,7 +153,7 @@ nlmclnt_recovery(struct nlm_host *host)
 	if (!host->h_reclaiming++) {
 		nlm_get_host(host);
 		__module_get(THIS_MODULE);
-		if (kernel_thread(reclaimer, host, CLONE_KERNEL) < 0)
+		if (kernel_thread(reclaimer, host, CLONE_FS | CLONE_FILES) < 0)
 			module_put(THIS_MODULE);
 	}
 }