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0e66100637
Stopping the vb2 thread (as used by several DVB devices) can result in an 'UNBALANCED' warning such as this: vb2: counters for queue ffff880407ee9828: UNBALANCED! vb2: setup: 1 start_streaming: 1 stop_streaming: 1 vb2: wait_prepare: 249333 wait_finish: 249334 This is due to a race condition between stopping the thread and calling vb2_internal_streamoff(). While I have not been able to deduce the exact mechanism how this race condition can produce this warning, I can see that the way the stream is stopped is likely to lead to a race somewhere. This patch simplifies how this is done by first ensuring that the thread is completely stopped before cleaning up the vb2 queue. It does that by setting threadio->stop to true, followed by a call to vb2_queue_error() which will wake up the thread. The thread sees that 'stop' is true and it will exit. The call to kthread_stop() waits until the thread has exited, and only then is the queue cleaned up by calling __vb2_cleanup_fileio(). This is a much cleaner sequence and the warning has now disappeared. Reported-by: Jurgen Kramer <gtmkramer@xs4all.nl> Tested-by: Jurgen Kramer <gtmkramer@xs4all.nl> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v3.18 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| tuner-core.c | ||
| v4l2-async.c | ||
| v4l2-clk.c | ||
| v4l2-common.c | ||
| v4l2-compat-ioctl32.c | ||
| v4l2-ctrls.c | ||
| v4l2-dev.c | ||
| v4l2-device.c | ||
| v4l2-dv-timings.c | ||
| v4l2-event.c | ||
| v4l2-fh.c | ||
| v4l2-ioctl.c | ||
| v4l2-mem2mem.c | ||
| v4l2-of.c | ||
| v4l2-subdev.c | ||
| videobuf2-core.c | ||
| videobuf2-dma-contig.c | ||
| videobuf2-dma-sg.c | ||
| videobuf2-dvb.c | ||
| videobuf2-memops.c | ||
| videobuf2-vmalloc.c | ||
| videobuf-core.c | ||
| videobuf-dma-contig.c | ||
| videobuf-dma-sg.c | ||
| videobuf-dvb.c | ||
| videobuf-vmalloc.c | ||