crash while encoding from x11grab when source goes away

[Omry Yadan]

Summary of the bug:
ffmpeg crashes when it's grabbing frames using x11grab if the source of the frames shutsdown unexpectedly.

How to reproduce:

# Start an xvfb vistual frame buffer:
Xvfb :100 -screen 0 1600x1200x24

# Optional, run something inside:
DISPLAY=:100 xterm

# Capture frames to a file
~/build/bin/ffmpeg -f x11grab -video_size 1024x768 -i :100 -codec:v libx264  out.mp4 -y

# Ctrl C the Xvfb process, the ffmpeg process will segfault reliably.

I initially saw it on 2.8.14-0ubuntu0.16.04.1, but reproduced after building from the latest source from git as of July/9/2018).

Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker.

[Carl Eugen Hoyos]

Please test current FFmpeg git head and provide the command line including complete, uncut console output and backtrace, disassembly and register dump as explained on https://ffmpeg.org/bugreports.html to make this a valid ticket.

[Omry Yadan]

Added requested outputs.

[Andriy Gelman]

Fixed in ​2250dc40443a2b1e54a8fbcaae9402fcaa1538dd