From 7f70d7a9450b321585fbfd1eb977548d4264b2a6 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Sebastian=20Dr=C3=B6ge?= Date: Mon, 7 Jan 2019 14:08:00 +0200 Subject: [PATCH] bin: Hold the state lock while removing elements from a bin We need to take the state lock here to ensure that we're not currently just before setting the state of this child element. Otherwise it can happen that we removed the element here and e.g. set it to NULL state, and shortly afterwards have another thread set it to a higher state again as part of a state change for the whole bin. When adding an element to the bin this is not needed as we require callers to always ensure after adding to the bin that the new element is set to the correct state. --- gst/gstbin.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/gst/gstbin.c b/gst/gstbin.c index e5d4ecd..d9060c8 100644 --- a/gst/gstbin.c +++ b/gst/gstbin.c @@ -1864,6 +1864,19 @@ gst_bin_remove (GstBin * bin, GstElement * element) if (G_UNLIKELY (bclass->remove_element == NULL)) goto no_function; + /* We need to take the state lock here to ensure that we're + * not currently just before setting the state of this child + * element. Otherwise it can happen that we removed the element + * here and e.g. set it to NULL state, and shortly afterwards + * have another thread set it to a higher state again as part of + * a state change for the whole bin. + * + * When adding an element to the bin this is not needed as we + * require callers to always ensure after adding to the bin that + * the new element is set to the correct state. + */ + GST_STATE_LOCK (bin); + GST_CAT_DEBUG (GST_CAT_PARENTAGE, "removing element %s from bin %s", GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (bin)); @@ -1871,6 +1884,8 @@ gst_bin_remove (GstBin * bin, GstElement * element) result = bclass->remove_element (bin, element); GST_TRACER_BIN_REMOVE_POST (bin, result); + GST_STATE_UNLOCK (bin); + return result; /* ERROR handling */ -- 2.7.4