tipc: Fix recursive spinlock invocation in print buffer code

This patch fixes two routines that allow the global print buffer
spinlock to be taken recursively.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 5 deletions

diff --git a/net/tipc/dbg.c b/net/tipc/dbg.c
index c6806910598c..834319e3b7e7 100644
--- a/net/tipc/dbg.c
+++ b/net/tipc/dbg.c
@@ -179,8 +179,10 @@ void tipc_printbuf_move(struct print_buf *pb_to, struct print_buf *pb_from)
 	}
 
 	if (pb_to->size < pb_from->size) {
-		tipc_printbuf_reset(pb_to);
-		tipc_printf(pb_to, "*** PRINT BUFFER MOVE ERROR ***");
+		strcpy(pb_to->buf, "*** PRINT BUFFER MOVE ERROR ***");
+		pb_to->buf[pb_to->size - 1] = ~0;
+		pb_to->crs = strchr(pb_to->buf, 0);
+		pb_to->next = NULL;
 		return;
 	}
 
@@ -405,27 +407,32 @@ struct sk_buff *tipc_log_dump(void)
 	struct sk_buff *reply;
 
 	spin_lock_bh(&print_lock);
-	if (!TIPC_LOG->buf)
+	if (!TIPC_LOG->buf) {
+		spin_unlock_bh(&print_lock);
 		reply = tipc_cfg_reply_ultra_string("log not activated\n");
-	else if (tipc_printbuf_empty(TIPC_LOG))
+	} else if (tipc_printbuf_empty(TIPC_LOG)) {
+		spin_unlock_bh(&print_lock);
 		reply = tipc_cfg_reply_ultra_string("log is empty\n");
+	}
 	else {
 		struct tlv_desc *rep_tlv;
 		struct print_buf pb;
 		int str_len;
 
 		str_len = min(TIPC_LOG->size, 32768u);
+		spin_unlock_bh(&print_lock);
 		reply = tipc_cfg_reply_alloc(TLV_SPACE(str_len));
 		if (reply) {
 			rep_tlv = (struct tlv_desc *)reply->data;
 			tipc_printbuf_init(&pb, TLV_DATA(rep_tlv), str_len);
+			spin_lock_bh(&print_lock);
 			tipc_printbuf_move(&pb, TIPC_LOG);
+			spin_unlock_bh(&print_lock);
 			str_len = strlen(TLV_DATA(rep_tlv)) + 1;
 			skb_put(reply, TLV_SPACE(str_len));
 			TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
 		}
 	}
-	spin_unlock_bh(&print_lock);
 	return reply;
 }