[gstreamer] video playback deadlocks with v4l2 m2m devices

When a v4l2 m2m device is used for decoding a video,  qtmultimedia deadlocks in the gstreamer_element_seek() call at QGstPipeline::seek().

Backtrace shows that lockup happens in the gst_v4l2_video_dec object:

1. Qt calls the seek which causes the pipeline to emit `gst_pad_push_event()` events
2. when the v4l2h264dec is reached, gst_pad_stop_task() is called on the source pad
3. this leads to a GST_PAD_STREAM_LOCK (pad)

In another thread,

1. the decoder thread is started with its lock being hold:
   • lock
   • task function call
2. task function (gst_v4l2_video_dec_loop) polls the video device and waits for buffers

The stream lock from the first thread is the task lock from the second thread, so the first thread (called from Qt) blocks until video device provides a buffer.  This does not happen so that gst_pad_stop_task() blocks.

Issue was first seen with https://code.qt.io/cgit/qt/qtmultimedia.git/commit/src/plugins/multimedia/gstreamer/common/qgstpipeline.cpp?id=c7c1ac73d0f3bb5f6c97cd836347d27273708456

But this commit is ok and triggers the deadlock probably due to synchronized state changes.

Pipeline

Stacktrace Task 1

#0  __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:46
#1  0xa5b1ae4a in futex_wait (private=0, expected=2, futex_word=0xa0951e20) at /usr/src/debug/glibc/2.39+git/sysdeps/nptl/futex-internal.h:146
#2  {}GI{}_lll_lock_wait (futex=futex@entry=0xa0951e20, private=0) at lowlevellock.c:49
#3  0xa5b1f7a8 in lll_mutex_lock_optimized (mutex=0xa0951e20) at pthread_mutex_lock.c:48
#4  ___pthread_mutex_lock (mutex=0xa0951e20) at pthread_mutex_lock.c:128
#5  0x9d0b9836 in gst_pad_stop_task (pad=0xa0956808 [GstPad|src]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:6514
#6  0x9938d6ea in gst_v4l2_video_dec_sink_event (decoder=0xa09551b8 [v4l2h264dec|v4l2h264dec0], event=<optimized out>) at /usr/src/debug/gstreamer1.0-plugins-good/1.24.6/sys/v4l2/gstv4l2videodec.c:1188
#7  0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0xa0954bd8 [GstPad|sink], event=event@entry=0x173b068 [GstEvent], type=type@entry=320) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#8  0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x9d34ff20 [GstPad|src], event=event@entry=0x173b068 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#9  0x9d0b84f6 in gst_pad_push_event (pad=0x9d34ff20 [GstPad|src], event=0x173b068 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#10 0x9ce9be7a in gst_capsfilter_sink_event (trans=0x9d34f9f8 [GstCapsFilter|capsfilter0], event=0x173b068 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/plugins/elements/gstcapsfilter.c:527
#11 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x9d34fc00 [GstPad|sink], event=event@entry=0x173b068 [GstEvent], type=type@entry=320) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#12 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x9d34ca20 [GstPad|src], event=event@entry=0x173b068 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#13 0x9d0b84f6 in gst_pad_push_event (pad=0x9d34ca20 [GstPad|src], event=event@entry=0x173b068 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#14 0x9d153c44 in gst_base_parse_sink_event_default (parse=0x9d34be58 [GstH264Parse|h264parse0], event=<optimized out>) at /usr/src/debug/gstreamer1.0/1.24.6/libs/gst/base/gstbaseparse.c:1561
#15 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x9d34c708 [GstPad|sink], event=event@entry=0x173b068 [GstEvent], type=type@entry=320) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#16 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x9d349328 [GstMultiQueuePad|src_0], event=event@entry=0x173b068 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#17 0x9d0b84f6 in gst_pad_push_event (pad=pad@entry=0x9d349328 [GstMultiQueuePad|src_0], event=event@entry=0x173b068 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#18 0x9ceba232 in gst_multi_queue_sink_event (pad=<optimized out>, parent=0x9d347b30 [GstMultiQueue|multiqueue0], event=0x173b068 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/plugins/elements/gstmultiqueue.c:2687
#19 0x9d0b056e in gst_pad_send_event_unchecked (pad=pad@entry=0x9d348f50 [GstMultiQueuePad|sink_0], event=event@entry=0x173b068 [GstEvent], type=type@entry=320) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5970
#20 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x9d3460f0 [GstPad|video_0], event=event@entry=0x173b068 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#21 0x9d0b84f6 in gst_pad_push_event (pad=0x9d3460f0 [GstPad|video_0], event=event@entry=0x173b068 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#22 0x9a4b3086 in gst_matroska_demux_send_event (demux=demux@entry=0x9b76c6e8 [GstMatroskaDemux|matroskademux0], event=event@entry=0x173b068 [GstEvent]) at /usr/src/debug/gstreamer1.0-plugins-good/1.24.6/gst/matroska/matroska-demux.c:1972
#23 0x9a4c3e12 in gst_matroska_demux_handle_seek_event (demux=demux@entry=0x9b76c6e8 [GstMatroskaDemux|matroskademux0], pad=pad@entry=0x9d3460f0 [GstPad|video_0], event=event@entry=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0-plugins-good/1.24.6/gst/matroska/matroska-demux.c:2955
#24 0x9a4c49a6 in gst_matroska_demux_handle_src_event (pad=0x9d3460f0 [GstPad|video_0], parent=0x9b76c6e8 [GstMatroskaDemux|matroskademux0], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0-plugins-good/1.24.6/gst/matroska/matroska-demux.c:3242
#25 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x9d3460f0 [GstPad|video_0], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#26 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x9d348f50 [GstMultiQueuePad|sink_0], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#27 0x9d0b84f6 in gst_pad_push_event (pad=pad@entry=0x9d348f50 [GstMultiQueuePad|sink_0], event=event@entry=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#28 0x9ceb79da in gst_multi_queue_src_event (pad=0x9d349328 [GstMultiQueuePad|src_0], parent=<optimized out>, event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/plugins/elements/gstmultiqueue.c:3003
#29 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x9d349328 [GstMultiQueuePad|src_0], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#30 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x9d34c708 [GstPad|sink], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#31 0x9d0b84f6 in gst_pad_push_event (pad=pad@entry=0x9d34c708 [GstPad|sink], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#32 0x9d14fb1e in gst_base_parse_handle_seek (event=0x16e2dc0 [GstEvent], parse=0x9d34be58 [GstH264Parse|h264parse0]) at /usr/src/debug/gstreamer1.0/1.24.6/libs/gst/base/gstbaseparse.c:4618
#33 gst_base_parse_src_event_default (parse=0x9d34be58 [GstH264Parse|h264parse0], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/libs/gst/base/gstbaseparse.c:1740
#34 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x9d34ca20 [GstPad|src], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#35 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x9d34fc00 [GstPad|sink], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#36 0x9d0b84f6 in gst_pad_push_event (pad=0x9d34fc00 [GstPad|sink], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#37 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x9d34ff20 [GstPad|src], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#38 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0xa0954bd8 [GstPad|sink], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#39 0x9d0b84f6 in gst_pad_push_event (pad=0xa0954bd8 [GstPad|sink], event=event@entry=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#40 0x9d1bd3ca in gst_video_decoder_src_event_default (decoder=0xa09551b8 [v4l2h264dec|v4l2h264dec0], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0-plugins-base/1.24.6/gst-libs/gst/video/gstvideodecoder.c:1795
#41 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0xa0956808 [GstPad|src], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#42 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x9d348238 [GstProxyPad|proxypad4], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#43 0x9d0b84f6 in gst_pad_push_event (pad=pad@entry=0x9d348238 [GstProxyPad|proxypad4], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#44 0x9d0b8918 in event_forward_func (pad=0x9d348238 [GstProxyPad|proxypad4], data=0xaed07d10) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3156
#45 0x9d0b5650 in gst_pad_forward (pad=pad@entry=0x9d348060 [GstDecodePad|src_0], forward=0x9d0b88f5 <event_forward_func>, user_data=user_data@entry=0xaed07d10) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3110
#46 0x9d0b570c in gst_pad_event_default (pad=0x9d348060 [GstDecodePad|src_0], parent=<optimized out>, event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3207
#47 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x9d348060 [GstDecodePad|src_0], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#48 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0xa0802680 [GstProxyPad|proxypad5], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#49 0x9d0b84f6 in gst_pad_push_event (pad=pad@entry=0xa0802680 [GstProxyPad|proxypad5], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#50 0x9d0b8918 in event_forward_func (pad=0xa0802680 [GstProxyPad|proxypad5], data=0xaed07f30) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3156
#51 0x9d0b5650 in gst_pad_forward (pad=pad@entry=0xa0803348 [GstGhostPad|src_0], forward=0x9d0b88f5 <event_forward_func>, user_data=user_data@entry=0xaed07f30) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3110
#52 0x9d0b570c in gst_pad_event_default (pad=0xa0803348 [GstGhostPad|src_0], parent=<optimized out>, event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3207
#53 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0xa0803348 [GstGhostPad|src_0], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#54 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0xa0803598 [GstSelectorPad|sink_0], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#55 0x9d0b84f6 in gst_pad_push_event (pad=pad@entry=0xa0803598 [GstSelectorPad|sink_0], event=event@entry=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#56 0x9ceb1b7e in gst_input_selector_event (pad=0x16c2670 [GstPad|src], parent=0x16c2528 [GstInputSelector|videoInputSelector], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/plugins/elements/gstinputselector.c:1677
#57 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x16c2670 [GstPad|src], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#58 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x16c4790 [GstGhostPad|sink], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#59 0x9d0b84f6 in gst_pad_push_event (pad=pad@entry=0x16c4790 [GstGhostPad|sink], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#60 0x9d0b8918 in event_forward_func (pad=0x16c4790 [GstGhostPad|sink], data=0xaed08300) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3156
#61 0x9d0b5650 in gst_pad_forward (pad=pad@entry=0x16c2f60 [GstProxyPad|proxypad0], forward=0x9d0b88f5 <event_forward_func>, user_data=user_data@entry=0xaed08300) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3110
#62 0x9d0b570c in gst_pad_event_default (pad=0x16c2f60 [GstProxyPad|proxypad0], parent=<optimized out>, event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3207
#63 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x16c2f60 [GstProxyPad|proxypad0], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#64 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x16b4190 [GstPad|sink], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#65 0x9d0b84f6 in gst_pad_push_event (pad=pad@entry=0x16b4190 [GstPad|sink], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#66 0x9d0b8918 in event_forward_func (pad=0x16b4190 [GstPad|sink], data=0xaed08520) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3156
#67 0x9d0b5650 in gst_pad_forward (pad=pad@entry=0x16b4438 [GstPad|src], forward=0x9d0b88f5 <event_forward_func>, user_data=user_data@entry=0xaed08520) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3110
#68 0x9d0b570c in gst_pad_event_default (pad=0x16b4438 [GstPad|src], parent=<optimized out>, event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3207
#69 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x16b4438 [GstPad|src], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#70 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x16b7e60 [GstPad|sink], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#71 0x9d0b84f6 in gst_pad_push_event (pad=0x16b7e60 [GstPad|sink], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#72 0x9ce8d2b0 in gst_video_convert_scale_src_event (trans=0x16b7b68 [GstVideoConvertScale|videoConvertScale], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0-plugins-base/1.24.6/gst/videoconvertscale/gstvideoconvertscale.c:1848
#73 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x16b8028 [GstPad|src], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#74 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x16c5a30 [GstGhostPad|sink], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#75 0x9d0b84f6 in gst_pad_push_event (pad=pad@entry=0x16c5a30 [GstGhostPad|sink], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#76 0x9d0b8918 in event_forward_func (pad=0x16c5a30 [GstGhostPad|sink], data=0xaed088d0) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3156
#77 0x9d0b5650 in gst_pad_forward (pad=pad@entry=0x16c5cb0 [GstProxyPad|proxypad1], forward=0x9d0b88f5 <event_forward_func>, user_data=user_data@entry=0xaed088d0) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3110
#78 0x9d0b570c in gst_pad_event_default (pad=0x16c5cb0 [GstProxyPad|proxypad1], parent=<optimized out>, event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:3207
#79 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x16c5cb0 [GstProxyPad|proxypad1], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#80 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x16c1520 [GstPad|sink], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#81 0x9d0b84f6 in gst_pad_push_event (pad=0x16c1520 [GstPad|sink], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#82 0x9d0b0956 in gst_pad_send_event_unchecked (pad=pad@entry=0x16c17f0 [GstPad|src], event=event@entry=0x16e2dc0 [GstEvent], type=type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5971
#83 0x9d0b0ec0 in gst_pad_push_event_unchecked (pad=pad@entry=0x9de55310 [GstPad|sink], event=event@entry=0x16e2dc0 [GstEvent], type=<optimized out>, type@entry=GST_PAD_PROBE_TYPE_EVENT_UPSTREAM) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5604
#84 0x9d0b84f6 in gst_pad_push_event (pad=pad@entry=0x9de55310 [GstPad|sink], event=event@entry=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpad.c:5743
#85 0x9d15c19c in gst_base_sink_send_event (element=0x9de54dd0 [QGstVideoRendererSink|qgstvideorenderersink1], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/libs/gst/base/gstbasesink.c:5129
#86 0x9d098648 in gst_element_send_event (element=element@entry=0x9de54dd0 [QGstVideoRendererSink|qgstvideorenderersink1], event=event@entry=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstelement.c:1994
#87 0x9d07e928 in gst_bin_send_event (element=0x16c0868 [GstBin|videoSinkBin], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstbin.c:3137
#88 0x9d098648 in gst_element_send_event (element=element@entry=0x16c0868 [GstBin|videoSinkBin], event=event@entry=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstelement.c:1994
#89 0x9d07e928 in gst_bin_send_event (element=0x16b0bf0 [GstBin|videoOutput], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstbin.c:3137
#90 0x9d098648 in gst_element_send_event (element=element@entry=0x16b0bf0 [GstBin|videoOutput], event=event@entry=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstelement.c:1994
#91 0x9d07e928 in gst_bin_send_event (element=0x16c3be8 [GstPipeline|playerPipeline], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstbin.c:3137
#92 0x9d098648 in gst_element_send_event (element=0x16c3be8 [GstPipeline|playerPipeline], event=0x16e2dc0 [GstEvent]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstelement.c:1994
#93 0x9d2f3b8e in QGstPipeline::seek (this=0x166ff44, pos=..., rate=1) at /usr/include/c++/13.3.0/bits/chrono.h:589
#94 0x9d953108 in QMediaPlayerPrivate::setMedia (this=this@entry=0x15c2710, media=..., stream=stream@entry=0x0) at /usr/src/debug/qtmultimedia/6.7.3/src/multimedia/playback/qmediaplayer.cpp:198
#95 0x9d953bae in QMediaPlayer::setSource (this=this@entry=0x9de03828, source=...) at /usr/src/debug/qtmultimedia/6.7.3/src/multimedia/playback/qmediaplayer.cpp:618
#96 0x9df8be24 in QQuickMediaPlayer::qmlSetSource (this=this@entry=0x9de03828, source=...) at /usr/src/debug/qtmultimedia/6.7.3/src/multimediaquick/qquickmediaplayer.cpp:24
#97 0x9df8bee2 in QQuickMediaPlayer::qt_static_metacall (_o=_o@entry=0x9de03828, _c=_c@entry=QMetaObject::WriteProperty, _id=_id@entry=0, _a=_a@entry=0xaed0a080) at /usr/src/debug/qtmultimedia/6.7.3/src/multimediaquick/MultimediaQuickPrivate_autogen/include/moc_qquickmediaplayer_p.cpp:184
#98 0x9df8c02a in QQuickMediaPlayer::qt_metacall (this=0x9de03828, _c=QMetaObject::WriteProperty, _id=0, _a=0xaed0a080) at /usr/src/debug/qtmultimedia/6.7.3/src/multimediaquick/MultimediaQuickPrivate_autogen/include/moc_qquickmediaplayer_p.cpp:223
#99 0xa6dc564c in ??? () at /lib/libQt6Qml.so.6

Stacktrace Thread 2

#0  __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:46
#1  0xa5b63c60 in {}GI{}_ppoll64 (fds=0xa080a7b0, nfds=2, timeout=<optimized out>, sigmask=sigmask@entry=0x0) at /usr/src/debug/glibc/2.39+git/sysdeps/unix/sysv/linux/ppoll.c:42
#2  0x9d0c2656 in gst_poll_wait (set=0xa0956088, timeout=<optimized out>) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gstpoll.c:1468
#3  0x9938120e in gst_v4l2_object_poll (v4l2object=0xa0956d38, timeout=<optimized out>) at /usr/src/debug/gstreamer1.0-plugins-good/1.24.6/sys/v4l2/gstv4l2object.c:5836
#4  0x99381eb0 in gst_v4l2_buffer_pool_poll (pool=pool@entry=0xa0804cf8 [GstV4l2BufferPool|v4l2h264dec0:pool0:src], wait=wait@entry=1) at /usr/src/debug/gstreamer1.0-plugins-good/1.24.6/sys/v4l2/gstv4l2bufferpool.c:1144
#5  0x99383596 in gst_v4l2_buffer_pool_dqbuf (pool=pool@entry=0xa0804cf8 [GstV4l2BufferPool|v4l2h264dec0:pool0:src], buffer=buffer@entry=0x99000aec, outstanding=outstanding@entry=0x0, wait=wait@entry=1) at /usr/src/debug/gstreamer1.0-plugins-good/1.24.6/sys/v4l2/gstv4l2bufferpool.c:1251
#6  0x993845f2 in gst_v4l2_buffer_pool_process (pool=pool@entry=0xa0804cf8 [GstV4l2BufferPool|v4l2h264dec0:pool0:src], buf=buf@entry=0x99000b6c, frame_number=frame_number@entry=0x0) at /usr/src/debug/gstreamer1.0-plugins-good/1.24.6/sys/v4l2/gstv4l2bufferpool.c:1983
#7  0x9938e0de in gst_v4l2_video_dec_loop (decoder=0xa09551b8 [v4l2h264dec|v4l2h264dec0]) at /usr/src/debug/gstreamer1.0-plugins-good/1.24.6/sys/v4l2/gstv4l2videodec.c:784
#8  0x9d0dc254 in gst_task_func (task=0xa09461f8 [GstTask|v4l2h264dec0:src]) at /usr/src/debug/gstreamer1.0/1.24.6/gst/gsttask.c:400
#9  0xa5851510 in g_thread_pool_thread_proxy (data=<optimized out>) at /usr/src/debug/glib-2.0/2.78.6/glib/gthreadpool.c:350
#10 0xa5850cfe in g_thread_proxy (data=0x9c500d80) at /usr/src/debug/glib-2.0/2.78.6/glib/gthread.c:831
#11 0xa5b1d1dc in start_thread (arg=0x696c6720) at pthread_create.c:447
#12 0xa5b6abf8 in ??? () at ../sysdeps/unix/sysv/linux/arm/clone3.S:71