diff --git a/Makefile b/Makefile
index 55972b1..743c123 100644
--- a/Makefile
+++ b/Makefile
@@ -33,7 +33,8 @@ AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/MIPS64EL/MIPSEL64/')
 AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/HPPA/PARISC/')
 AUDIT_ARCH := $(shell echo $(AUDIT_ARCH) | sed 's/SH4/SH/')
 
-FLAGS := -Wall -Wextra -pedantic -std=c11 -D_XOPEN_SOURCE=700 -D_GNU_SOURCE
+FLAGS := -Wall -Wextra -Wno-format-zero-length
+FLAGS += -pedantic -std=c11 -D_XOPEN_SOURCE=700 -D_GNU_SOURCE
 FLAGS += -D_FORTIFY_SOURCE=2 -O2 -pie -fPIE
 FLAGS += -DPAGE_SIZE=$(shell getconf PAGE_SIZE)
 FLAGS += -DNETNS_RUN_DIR=\"/run/netns\"
diff --git a/conf.c b/conf.c
index d3e6eb2..a79beb5 100644
--- a/conf.c
+++ b/conf.c
@@ -493,7 +493,7 @@ static void conf_netns_opt(char *netns, const char *arg)
 	}
 
 	if (ret <= 0 || ret > PATH_MAX)
-		die("Network namespace name/path %s too long");
+		die("Network namespace name/path %s too long", arg);
 }
 
 /**
diff --git a/log.h b/log.h
index b4fb7e9..df72f9a 100644
--- a/log.h
+++ b/log.h
@@ -12,7 +12,8 @@
 #define LOGFILE_CUT_RATIO		30	/* When full, cut ~30% size */
 #define LOGFILE_SIZE_MIN		(5UL * MAX(BUFSIZ, PAGE_SIZE))
 
-void logmsg(int pri, const char *format, ...);
+void logmsg(int pri, const char *format, ...)
+	__attribute__((format(printf, 2, 3)));
 
 #define err(...)	logmsg(LOG_ERR, __VA_ARGS__)
 #define warn(...)	logmsg(LOG_WARNING, __VA_ARGS__)
diff --git a/packet.c b/packet.c
index 693e034..9589824 100644
--- a/packet.c
+++ b/packet.c
@@ -43,13 +43,14 @@ void packet_add_do(struct pool *p, size_t len, const char *start,
 
 	if (start < p->buf) {
 		trace("add packet start %p before buffer start %p, %s:%i",
-		      start, p->buf, func, line);
+		      (void *)start, (void *)p->buf, func, line);
 		return;
 	}
 
 	if (start + len > p->buf + p->buf_size) {
 		trace("add packet start %p, length: %lu, buffer end %p, %s:%i",
-		      start, len, p->buf + p->buf_size, func, line);
+		      (void *)start, len, (void *)(p->buf + p->buf_size),
+		      func, line);
 		return;
 	}
 
@@ -61,7 +62,7 @@ void packet_add_do(struct pool *p, size_t len, const char *start,
 #if UINTPTR_MAX == UINT64_MAX
 	if ((uintptr_t)start - (uintptr_t)p->buf > UINT32_MAX) {
 		trace("add packet start %p, buffer start %p, %s:%i",
-		      start, p->buf, func, line);
+		      (void *)start, (void *)p->buf, func, line);
 		return;
 	}
 #endif
diff --git a/pasta.c b/pasta.c
index 5fd44fe..94807a3 100644
--- a/pasta.c
+++ b/pasta.c
@@ -239,7 +239,7 @@ void pasta_start_ns(struct ctx *c, uid_t uid, gid_t gid,
 
 		if ((size_t)snprintf(sh_arg0, sizeof(sh_arg0),
 				     "-%s", arg.exe) >= sizeof(sh_arg0))
-			die("$SHELL is too long (%u bytes)", strlen(arg.exe));
+			die("$SHELL is too long (%zu bytes)", strlen(arg.exe));
 
 		sh_argv[0] = sh_arg0;
 		arg.argv = sh_argv;
diff --git a/tcp.c b/tcp.c
index a1ff66d..19d16a6 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1212,7 +1212,8 @@ static void tcp_hash_insert(const struct ctx *c, struct tcp_tap_conn *conn)
 	tc_hash[b] = conn;
 
 	debug("TCP: hash table insert: index %li, sock %i, bucket: %i, next: "
-	      "%p", CONN_IDX(conn), conn->sock, b, conn_at_idx(conn->next_index));
+	      "%p", CONN_IDX(conn), conn->sock, b,
+	      (void *)conn_at_idx(conn->next_index));
 }
 
 /**
@@ -1239,7 +1240,7 @@ static void tcp_hash_remove(const struct ctx *c,
 
 	debug("TCP: hash table remove: index %li, sock %i, bucket: %i, new: %p",
 	      CONN_IDX(conn), conn->sock, b,
-	      prev ? conn_at_idx(prev->next_index) : tc_hash[b]);
+	      (void *)(prev ? conn_at_idx(prev->next_index) : tc_hash[b]));
 }
 
 /**
@@ -1267,7 +1268,8 @@ static void tcp_tap_conn_update(const struct ctx *c, struct tcp_tap_conn *old,
 
 	debug("TCP: hash table update: old index %li, new index %li, sock %i, "
 	      "bucket: %i, old: %p, new: %p",
-	      CONN_IDX(old), CONN_IDX(new), new->sock, b, old, new);
+	      CONN_IDX(old), CONN_IDX(new), new->sock, b,
+	      (void *)old, (void *)new);
 
 	tcp_epoll_ctl(c, new);
 }
@@ -1311,7 +1313,7 @@ void tcp_table_compact(struct ctx *c, union tcp_conn *hole)
 
 	if (CONN_IDX(hole) == --c->tcp.conn_count) {
 		debug("TCP: table compaction: maximum index was %li (%p)",
-		      CONN_IDX(hole), hole);
+		      CONN_IDX(hole), (void *)hole);
 		memset(hole, 0, sizeof(*hole));
 		return;
 	}
@@ -1326,7 +1328,8 @@ void tcp_table_compact(struct ctx *c, union tcp_conn *hole)
 
 	debug("TCP: table compaction (spliced=%d): old index %li, new index %li, "
 	      "from: %p, to: %p",
-	      from->c.spliced, CONN_IDX(from), CONN_IDX(hole), from, hole);
+	      from->c.spliced, CONN_IDX(from), CONN_IDX(hole),
+	      (void *)from, (void *)hole);
 
 	memset(from, 0, sizeof(*from));
 }