diff --git a/src/evrtsp/rtsp.c b/src/evrtsp/rtsp.c
index d579b09f..ea8ccc5a 100644
--- a/src/evrtsp/rtsp.c
+++ b/src/evrtsp/rtsp.c
@@ -1349,7 +1349,7 @@ evrtsp_connection_get_local_address(struct evrtsp_connection *evcon,
 
       default:
 	free(*address);
-	address = NULL;
+	*address = NULL;
 
 	event_err(1, "%s: unhandled address family\n", __func__);
 	return;
diff --git a/src/httpd_daap.c b/src/httpd_daap.c
index 0564275b..8a58f872 100644
--- a/src/httpd_daap.c
+++ b/src/httpd_daap.c
@@ -211,7 +211,7 @@ daap_session_add(const char *user_agent, int request_session_id)
 
   daap_session_cleanup();
 
-  s = (struct daap_session *)malloc(sizeof(struct daap_session));
+  s = calloc(1, sizeof(struct daap_session));
   if (!s)
     {
       DPRINTF(E_LOG, L_DAAP, "Out of memory for DAAP session\n");
@@ -225,6 +225,7 @@ daap_session_add(const char *user_agent, int request_session_id)
       if (daap_session_get(request_session_id))
 	{
 	  DPRINTF(E_LOG, L_DAAP, "Session id requested in login (%d) is not available\n", request_session_id);
+	  free(s);
 	  return NULL;
 	}
       
@@ -385,7 +386,7 @@ daap_sort_context_new(void)
   struct sort_ctx *ctx;
   int ret;
 
-  ctx = (struct sort_ctx *)malloc(sizeof(struct sort_ctx));
+  ctx = calloc(1, sizeof(struct sort_ctx));
   if (!ctx)
     {
       DPRINTF(E_LOG, L_DAAP, "Out of memory for sorting context\n");
@@ -532,14 +533,10 @@ user_agent_filter(const char *user_agent, struct query_params *qp)
 {
   const char *filter;
   char *buffer;
-  int len;
 
   if (!user_agent)
     return;
 
-  // Valgrind doesn't like strlen(filter) below, so instead we allocate 128 bytes
-  // to hold the string and the leading " AND ". Remember to adjust the 128 if
-  // you define strings here that will be too large for the buffer.
   if (is_remote(user_agent))
     filter = "(f.data_kind <> 1)"; // No internet radio
   else
@@ -547,12 +544,9 @@ user_agent_filter(const char *user_agent, struct query_params *qp)
 
   if (qp->filter)
     {
-      len = strlen(qp->filter) + 128;
-      buffer = (char *)malloc(len);
-      snprintf(buffer, len, "%s AND %s", qp->filter, filter);
+      buffer = safe_asprintf("%s AND %s", qp->filter, filter);
       free(qp->filter);
-      qp->filter = strdup(buffer);
-      free(buffer);
+      qp->filter = buffer;
     }
   else
     qp->filter = strdup(filter);
@@ -719,7 +713,7 @@ parse_meta(struct evhttp_request *req, char *tag, const char *param, const struc
 
   DPRINTF(E_DBG, L_DAAP, "Asking for %d meta tags\n", nmeta);
 
-  meta = (const struct dmap_field **)malloc(nmeta * sizeof(const struct dmap_field *));
+  meta = (const struct dmap_field **)calloc(nmeta, sizeof(const struct dmap_field *));
   if (!meta)
     {
       DPRINTF(E_LOG, L_DAAP, "Could not allocate meta array; out of memory\n");
@@ -1069,7 +1063,7 @@ daap_reply_update(struct evhttp_request *req, struct evbuffer *evbuf, char **uri
     }
 
   /* Else, just let the request hang until we have changes to push back */
-  ur = (struct daap_update_request *)malloc(sizeof(struct daap_update_request));
+  ur = calloc(1, sizeof(struct daap_update_request));
   if (!ur)
     {
       DPRINTF(E_LOG, L_DAAP, "Out of memory for update request\n");
diff --git a/src/library.c b/src/library.c
index 8c57f85b..287cbe5e 100644
--- a/src/library.c
+++ b/src/library.c
@@ -277,11 +277,11 @@ fixup_tags(struct media_file_info *mfi)
 
       if (!mfi->album)
 	{
-	  len = snprintf(NULL, 0, "%s, Season %d", mfi->tv_series_name, mfi->tv_season_num);
+	  len = snprintf(NULL, 0, "%s, Season %u", mfi->tv_series_name, mfi->tv_season_num);
 
 	  mfi->album = (char *)malloc(len + 1);
 	  if (mfi->album)
-	    sprintf(mfi->album, "%s, Season %d", mfi->tv_series_name, mfi->tv_season_num);
+	    sprintf(mfi->album, "%s, Season %u", mfi->tv_series_name, mfi->tv_season_num);
 	}
     }
 
diff --git a/src/library/filescanner_playlist.c b/src/library/filescanner_playlist.c
index 76f10ff8..7704d13f 100644
--- a/src/library/filescanner_playlist.c
+++ b/src/library/filescanner_playlist.c
@@ -248,7 +248,7 @@ scan_playlist(char *file, time_t mtime, int dir_id)
 	{
 	  DPRINTF(E_LOG, L_SCAN, "Out of memory\n");
 
-	  return;
+	  goto out_close;
 	}
 
       memset(pli, 0, sizeof(struct playlist_info));
@@ -270,7 +270,7 @@ scan_playlist(char *file, time_t mtime, int dir_id)
 	  DPRINTF(E_LOG, L_SCAN, "Error adding playlist '%s'\n", file);
 
 	  free_pli(pli, 0);
-	  return;
+	  goto out_close;
 	}
 
       DPRINTF(E_INFO, L_SCAN, "Added playlist as id %d\n", pl_id);
@@ -346,11 +346,11 @@ scan_playlist(char *file, time_t mtime, int dir_id)
     {
       DPRINTF(E_LOG, L_SCAN, "Error reading playlist '%s': %s\n", file, strerror(errno));
 
-      fclose(fp);
-      return;
+      goto out_close;
     }
 
-  fclose(fp);
-
   DPRINTF(E_INFO, L_SCAN, "Done processing playlist\n");
+
+ out_close:
+  fclose(fp);
 }
diff --git a/src/outputs/alsa.c b/src/outputs/alsa.c
index 8727c990..591f309d 100644
--- a/src/outputs/alsa.c
+++ b/src/outputs/alsa.c
@@ -133,14 +133,15 @@ prebuf_free(struct alsa_session *as)
 static void
 alsa_session_free(struct alsa_session *as)
 {
+  if (!as)
+    return;
+
   event_free(as->deferredev);
 
   prebuf_free(as);
 
   free(as->output_session);
   free(as);
-
-  as = NULL;
 }
 
 static void
@@ -654,7 +655,8 @@ buffer_write(struct alsa_session *as, uint8_t *buf, snd_pcm_sframes_t *avail, in
   if (ret != nsamp)
     DPRINTF(E_WARN, L_LAUDIO, "ALSA partial write detected\n");
 
-  *avail -= ret;
+  if (avail)
+    *avail -= ret;
 
   return 0;
 }
diff --git a/src/outputs/cast.c b/src/outputs/cast.c
index bc41ec0b..de9ff39e 100644
--- a/src/outputs/cast.c
+++ b/src/outputs/cast.c
@@ -509,6 +509,9 @@ squote_to_dquote(char *buf)
 static void
 cast_session_free(struct cast_session *cs)
 {
+  if (!cs)
+    return;
+
   event_free(cs->reply_timeout);
   event_free(cs->ev);
 
diff --git a/src/outputs/dummy.c b/src/outputs/dummy.c
index e5dfad2e..3083ead4 100644
--- a/src/outputs/dummy.c
+++ b/src/outputs/dummy.c
@@ -67,12 +67,13 @@ defer_cb(int fd, short what, void *arg);
 static void
 dummy_session_free(struct dummy_session *ds)
 {
+  if (!ds)
+    return;
+
   event_free(ds->deferredev);
 
   free(ds->output_session);
   free(ds);
-
-  ds = NULL;
 }
 
 static void
diff --git a/src/outputs/fifo.c b/src/outputs/fifo.c
index dd44ceb8..0aa7c10e 100644
--- a/src/outputs/fifo.c
+++ b/src/outputs/fifo.c
@@ -237,12 +237,14 @@ fifo_empty(struct fifo_session *fifo_session)
 static void
 fifo_session_free(struct fifo_session *fifo_session)
 {
+  if (!fifo_session)
+    return;
+
   event_free(fifo_session->deferredev);
 
   free(fifo_session->output_session);
   free(fifo_session);
   free_buffer();
-  fifo_session = NULL;
 }
 
 static void
diff --git a/src/outputs/pulse.c b/src/outputs/pulse.c
index 859c0553..b41a27ab 100644
--- a/src/outputs/pulse.c
+++ b/src/outputs/pulse.c
@@ -97,6 +97,9 @@ pulse_from_device_volume(int device_volume)
 static void
 pulse_session_free(struct pulse_session *ps)
 {
+  if (!ps)
+    return;
+
   if (ps->stream)
     {
       pa_threaded_mainloop_lock(pulse.mainloop);
diff --git a/src/outputs/raop.c b/src/outputs/raop.c
index beccb59c..fcc4b469 100644
--- a/src/outputs/raop.c
+++ b/src/outputs/raop.c
@@ -1368,7 +1368,7 @@ raop_send_req_flush(struct raop_session *rs, uint64_t rtptime, evrtsp_req_cb cb)
     }
 
   /* Restart sequence: last sequence + 1 */
-  ret = snprintf(buf, sizeof(buf), "seq=%u;rtptime=%u", stream_seq + 1, RAOP_RTPTIME(rtptime));
+  ret = snprintf(buf, sizeof(buf), "seq=%" PRIu16 ";rtptime=%u", stream_seq + 1, RAOP_RTPTIME(rtptime));
   if ((ret < 0) || (ret >= sizeof(buf)))
     {
       DPRINTF(E_LOG, L_RAOP, "RTP-Info too big for buffer in FLUSH request\n");
@@ -1468,7 +1468,7 @@ raop_send_req_record(struct raop_session *rs, evrtsp_req_cb cb)
   evrtsp_add_header(req->output_headers, "Range", "npt=0-");
 
   /* Start sequence: next sequence */
-  ret = snprintf(buf, sizeof(buf), "seq=%u;rtptime=%u", stream_seq + 1, RAOP_RTPTIME(rs->start_rtptime));
+  ret = snprintf(buf, sizeof(buf), "seq=%" PRIu16 ";rtptime=%u", stream_seq + 1, RAOP_RTPTIME(rs->start_rtptime));
   if ((ret < 0) || (ret >= sizeof(buf)))
     {
       DPRINTF(E_LOG, L_RAOP, "RTP-Info too big for buffer in RECORD request\n");
@@ -1778,6 +1778,9 @@ raop_status(struct raop_session *rs)
 static void
 raop_session_free(struct raop_session *rs)
 {
+  if (!rs)
+    return;
+
   evrtsp_connection_set_closecb(rs->ctrl, NULL, NULL);
 
   evrtsp_connection_free(rs->ctrl);
@@ -1802,8 +1805,6 @@ raop_session_free(struct raop_session *rs)
   free(rs->output_session);
 
   free(rs);
-
-  rs = NULL;
 }
 
 static void
@@ -3461,7 +3462,7 @@ raop_v2_resend_range(struct raop_session *rs, uint16_t seqnum, uint16_t len)
   /* Check that seqnum is in the retransmit buffer */
   if ((seqnum > pktbuf_head->seqnum) || (seqnum < pktbuf_tail->seqnum))
     {
-      DPRINTF(E_WARN, L_RAOP, "Device '%s' asking for seqnum %u; not in buffer (h %u t %u)\n", rs->devname, seqnum, pktbuf_head->seqnum, pktbuf_tail->seqnum);
+      DPRINTF(E_WARN, L_RAOP, "Device '%s' asking for seqnum %" PRIu16 "; not in buffer (h %" PRIu16 " t %" PRIu16 ")\n", rs->devname, seqnum, pktbuf_head->seqnum, pktbuf_tail->seqnum);
       return;
     }
 
diff --git a/src/outputs/raop_verification.c b/src/outputs/raop_verification.c
index e697211d..e534d923 100644
--- a/src/outputs/raop_verification.c
+++ b/src/outputs/raop_verification.c
@@ -702,14 +702,12 @@ srp_user_process_challenge(struct SRPUser *usr, const unsigned char *bytes_s, in
       calculate_H_AMK(usr->alg, usr->H_AMK, usr->A, usr->M, usr->session_key, usr->session_key_len);
         
       *bytes_M = usr->M;
-      if (len_M)
-        *len_M = hash_length(usr->alg);
+      *len_M   = hash_length(usr->alg);
     }
   else
     {
       *bytes_M = NULL;
-      if (len_M) 
-        *len_M   = 0;
+      *len_M   = 0;
     }
 
  cleanup2: