diff --git a/include/trace/events/9p.h b/include/trace/events/9p.h
index 4dfa6d7f83ba..cd104a1343e2 100644
--- a/include/trace/events/9p.h
+++ b/include/trace/events/9p.h
@@ -178,18 +178,21 @@ TRACE_EVENT(9p_protocol_dump,
 		    __field(	void *,		clnt				)
 		    __field(	__u8,		type				)
 		    __field(	__u16,		tag				)
-		    __array(	unsigned char,	line,	P9_PROTO_DUMP_SZ	)
+		    __dynamic_array(unsigned char, line,
+				min_t(size_t, pdu->capacity, P9_PROTO_DUMP_SZ))
 		    ),
 
 	    TP_fast_assign(
 		    __entry->clnt   =  clnt;
 		    __entry->type   =  pdu->id;
 		    __entry->tag    =  pdu->tag;
-		    memcpy(__entry->line, pdu->sdata, P9_PROTO_DUMP_SZ);
+		    memcpy(__get_dynamic_array(line), pdu->sdata,
+				__get_dynamic_array_len(line));
 		    ),
-	    TP_printk("clnt %lu %s(tag = %d)\n%.3x: %16ph\n%.3x: %16ph\n",
+	    TP_printk("clnt %lu %s(tag = %d)\n%*ph\n",
 		      (unsigned long)__entry->clnt, show_9p_op(__entry->type),
-		      __entry->tag, 0, __entry->line, 16, __entry->line + 16)
+		      __entry->tag, __get_dynamic_array_len(line),
+		      __get_dynamic_array(line))
  );
 
 
diff --git a/net/9p/protocol.c b/net/9p/protocol.c
index 4e3a2a1ffcb3..0e6603b1ec90 100644
--- a/net/9p/protocol.c
+++ b/net/9p/protocol.c
@@ -394,6 +394,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
 				uint16_t *nwname = va_arg(ap, uint16_t *);
 				char ***wnames = va_arg(ap, char ***);
 
+				*wnames = NULL;
+
 				errcode = p9pdu_readf(pdu, proto_version,
 								"w", nwname);
 				if (!errcode) {
@@ -403,6 +405,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
 							  GFP_NOFS);
 					if (!*wnames)
 						errcode = -ENOMEM;
+					else
+						(*wnames)[0] = NULL;
 				}
 
 				if (!errcode) {
@@ -414,8 +418,10 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
 								proto_version,
 								"s",
 								&(*wnames)[i]);
-						if (errcode)
+						if (errcode) {
+							(*wnames)[i] = NULL;
 							break;
+						}
 					}
 				}
 
@@ -423,11 +429,14 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
 					if (*wnames) {
 						int i;
 
-						for (i = 0; i < *nwname; i++)
+						for (i = 0; i < *nwname; i++) {
+							if (!(*wnames)[i])
+								break;
 							kfree((*wnames)[i]);
+						}
+						kfree(*wnames);
+						*wnames = NULL;
 					}
-					kfree(*wnames);
-					*wnames = NULL;
 				}
 			}
 			break;