diff --git a/libavdevice/avdevice.c b/libavdevice/avdevice.c
index 8964b96f36..ea14c7a286 100644
--- a/libavdevice/avdevice.c
+++ b/libavdevice/avdevice.c
@@ -101,6 +101,7 @@ int avdevice_dev_to_app_control_message(struct AVFormatContext *s, enum AVDevToA
 
 int avdevice_list_devices(AVFormatContext *s, AVDeviceInfoList **device_list)
 {
+    int ret;
     av_assert0(s);
     av_assert0(device_list);
     av_assert0(s->oformat || s->iformat);
@@ -113,8 +114,12 @@ int avdevice_list_devices(AVFormatContext *s, AVDeviceInfoList **device_list)
     if (!(*device_list))
         return AVERROR(ENOMEM);
     if (s->oformat)
-        return s->oformat->get_device_list(s, *device_list);
-    return s->iformat->get_device_list(s, *device_list);
+        ret = s->oformat->get_device_list(s, *device_list);
+    else
+        ret = s->iformat->get_device_list(s, *device_list);
+    if (ret < 0)
+        avdevice_free_list_devices(device_list);
+    return ret;
 }
 
 void avdevice_free_list_devices(AVDeviceInfoList **device_list)
diff --git a/libavformat/avio.c b/libavformat/avio.c
index a76f9db3b8..e366dfa388 100644
--- a/libavformat/avio.c
+++ b/libavformat/avio.c
@@ -270,7 +270,7 @@ int ffurl_open(URLContext **puc, const char *filename, int flags,
                const AVIOInterruptCB *int_cb, AVDictionary **options)
 {
     int ret = ffurl_alloc(puc, filename, flags, int_cb);
-    if (ret)
+    if (ret < 0)
         return ret;
     if (options && (*puc)->prot->priv_data_class &&
         (ret = av_opt_set_dict((*puc)->priv_data, options)) < 0)
@@ -399,7 +399,7 @@ int avio_check(const char *url, int flags)
 {
     URLContext *h;
     int ret = ffurl_alloc(&h, url, flags, NULL);
-    if (ret)
+    if (ret < 0)
         return ret;
 
     if (h->prot->url_check) {
diff --git a/libavformat/http.c b/libavformat/http.c
index 7a0ba6cedd..f693c4d0c6 100644
--- a/libavformat/http.c
+++ b/libavformat/http.c
@@ -979,16 +979,21 @@ static int64_t http_seek(URLContext *h, int64_t off, int whence)
     else if ((s->filesize == -1 && whence == SEEK_END) || h->is_streamed)
         return -1;
 
-    /* we save the old context in case the seek fails */
-    old_buf_size = s->buf_end - s->buf_ptr;
-    memcpy(old_buf, s->buf_ptr, old_buf_size);
-    s->hd = NULL;
     if (whence == SEEK_CUR)
         off += s->off;
     else if (whence == SEEK_END)
         off += s->filesize;
+    else if (whence != SEEK_SET)
+        return AVERROR(EINVAL);
+    if (off < 0)
+        return AVERROR(EINVAL);
     s->off = off;
 
+    /* we save the old context in case the seek fails */
+    old_buf_size = s->buf_end - s->buf_ptr;
+    memcpy(old_buf, s->buf_ptr, old_buf_size);
+    s->hd = NULL;
+
     /* if it fails, continue on old connection */
     av_dict_copy(&options, s->chained_options, 0);
     if (http_open_cnx(h, &options) < 0) {