appsrc: test_appsrc_push_buffer_list is racy

check.gst-plugins-base.elements_appsrc.test_appsrc_push_buffer_list: Failed 'Application returned 1'
       You can reproduce with: GST_PLUGIN_SYSTEM_PATH_1_0='' GST_TAG_LICENSE_TRANSLATIONS_DICT='/builds/gstreamer/gst-plugins-bad/gst-build/subprojects/gst-plugins-base/gst-libs/gst/tag/license-translations.dict' GST_REGISTRY='/builds/gstreamer/gst-plugins-bad/gst-build/build/subprojects/gst-plugins-base/tests/check/elements_appsrc.registry' GST_STATE_IGNORE_ELEMENTS='cdio cdparanoiasrc libvisual_ alsasrc alsasink' GST_PLUGIN_LOADING_WHITELIST='gstreamer:gst-plugins-base@/builds/gstreamer/gst-plugins-bad/gst-build/build' GST_CHECKS='test_appsrc_push_buffer_list' CK_DEFAULT_TIMEOUT='20' GST_PLUGIN_PATH_1_0='/builds/gstreamer/gst-plugins-bad/gst-build/build:/usr/local/lib64/gstreamer-1.0' /builds/gstreamer/gst-plugins-bad/gst-build/build/subprojects/gst-plugins-base/tests/check/elements_appsrc

Dumping log files on failure

Dumping contents of /builds/gstreamer/gst-plugins-bad/validate-output/logs/check/gst-plugins-base/elements_appsrc/test_appsrc_push_buffer_list

=================
Test name: check.gst-plugins-base.elements_appsrc.test_appsrc_push_buffer_list
Command: '/builds/gstreamer/gst-plugins-bad/gst-build/build/subprojects/gst-plugins-base/tests/check/elements_appsrc'
=================

Running suite(s): appsrc


Unexpected critical/warning: gst_buffer_list_get_writable: assertion 'gst_buffer_list_is_writable (list)' failed

Stack trace:
gst_debug_get_stack_trace (gstinfo.c:2788)
gst_check_log_critical_func (gstcheck.c:281)
g_logv (/usr/lib64/libglib-2.0.so.0.5800.1:0x7f67f09416db)
g_log (/usr/lib64/libglib-2.0.so.0.5800.1:0x7f67f09418cf)
gst_buffer_list_get_writable (gstbufferlist.c:380)
gst_base_src_get_range (gstbasesrc.c:2580)
gst_base_src_loop (gstbasesrc.c:2845)
gst_task_func (gsttask.c:328)
?? (/usr/lib64/libglib-2.0.so.0.5800.1:0x7f67f0963e8f)
?? (/usr/lib64/libglib-2.0.so.0.5800.1:0x7f67f0963486)
start_thread (/usr/lib64/libpthread-2.28.so:0x7f67f087b58a)
__clone (/usr/lib64/libc-2.28.so:0x7f67f07aa64f)

0%: Checks: 1, Failures: 1, Errors: 0
../subprojects/gstreamer/libs/gst/check/gstcheck.c:286:F:general:test_appsrc_push_buffer_list:0: Unexpected critical/warning: gst_buffer_list_get_writable: assertion 'gst_buffer_list_is_writable (list)' failed
Check suite appsrc ran in 0.011s (tests failed: 1)