When webcam stops says:

libv4l2: warning v4l2 mmap buffers still mapped on close()

but sometimes crashes:

*** glibc detected *** mono: double free or corruption (out):
0x00007f2954009ec0 ***
sensitiveGuiEventDone default
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x7eb96)[0x7f29affb2b96]
/usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0(gdk_region_intersect+0x72)[0x7f29a7d81942]
/usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0(+0x3ddff)[0x7f29a7d8bdff]
/usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0(gdk_window_process_all_updates+0x131)[0x7f29a7d8e201]
/usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0(+0xb8bb1)[0x7f29ac1b2bb1]
/usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0(+0x1de77)[0x7f29a7d6be77]
/lib/x86_64-linux-gnu/libglib-2.0.so.0(g_main_context_dispatch+0x135)[0x7f29a5fc7ab5]
/lib/x86_64-linux-gnu/libglib-2.0.so.0(+0x47de8)[0x7f29a5fc7de8]
/lib/x86_64-linux-gnu/libglib-2.0.so.0(g_main_loop_run+0x72)[0x7f29a5fc81e2]
/usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0(gtk_main+0xa7)[0x7f29ac22dc77]
[0x40923f75]
======= Memory map: ========
00400000-006e4000 r-xp 00000000 08:05 7471915
  /usr/bin/mono
008e4000-008e5000 r--p 002e4000 08:05 7471915
  /usr/bin/mono
008e5000-008ee000 rw-p 002e5000 08:05 7471915
  /usr/bin/mono
008ee000-00928000 rw-p 00000000 00:00 0
02312000-03f1d000 rw-p 00000000 00:00 0                                  [heap]
400f0000-40101000 rwxp 00000000 00:00 0
401d5000-401e6000 rwxp 00000000 00:00 0
401fc000-4020d000 rwxp 00000000 00:00 0
40289000-4028a000 r--p 00000000 00:00 0
4030c000-4031d000 rwxp 00000000 00:00 0
404f1000-40502000 rwxp 00000000 00:00 0
40631000-40642000 rwxp 00000000 00:00 0
4091e000-4092f000 rwxp 00000000 00:00 0
4096a000-4097b000 rwxp 00000000 00:00 0
40b01000-40b12000 rwxp 00000000 00:00 0
40c14000-40c25000 rwxp 00000000 00:00 0
40ce6000-40cf7000 rwxp 00000000 00:00 0
40fe3000-40fe4000 ---p 00000000 00:00 0
410ae000-410bf000 rwxp 00000000 00:00 0
410f2000-41103000 rwxp 00000000 00:00 0
412bf000-412d0000 rwxp 00000000 00:00 0
41447000-41458000 rwxp 00000000 00:00 0
4158f000-415a0000 rwxp 00000000 00:00 0
417e2000-417f3000 rwxp 00000000 00:00 0
417fa000-4180b000 rwxp 00000000 00:00 0
41c23000-41c34000 rwxp 00000000 00:00 0
41c89000-41c9a000 rwxp 00000000 00:00 0
7f2940000000-7f2940021000 rw-p 00000000 00:00 0
7f2940021000-7f2944000000 ---p 00000000 00:00 0
7f2948000000-7f2948022000 rw-p 00000000 00:00 0
7f2948022000-7f294c000000 ---p 00000000 00:00 0
7f294ffff000-7f2954000000 rw-s 00000000 00:12 324514
  /run/shm/pulse-shm-1180937595
7f2954000000-7f295405b000 rw-p 00000000 00:00 0
7f295405b000-7f2958000000 ---p 00000000 00:00 0
7f2958000000-7f2958021000 rw-p 00000000 00:00 0
7f2958021000-7f295c000000 ---p 00000000 00:00 0
7f295c000000-7f295c191000 rw-p 00000000 00:00 0
7f295c191000-7f2960000000 ---p 00000000 00:00 0
7f2960000000-7f2960022000 rw-p 00000000 00:00 0
7f2960022000-7f2964000000 ---p 00000000 00:00 0
7f2964000000-7f2964160000 rw-p 00000000 00:00 0
7f2964160000-7f2968000000 ---p 00000000 00:00 0
7f2968000000-7f2968022000 rw-p 00000000 00:00 0
7f2968022000-7f296c000000 ---p 00000000 00:00 0
7f296c7fd000-7f296c7fe000 ---p 00000000 00:00 0
7f296c7fe000-7f296cffe000 rw-p 00000000 00:00 0
  [stack:10308]
7f296cffe000-7f296cfff000 ---p 00000000 00:00 0
7f296cfff000-7f296d7ff000 rw-p 00000000 00:00 0
  [stack:10307]
7f296d7ff000-7f296d800000 ---p 00000000 00:00 0
7f296d800000-7f2970000000 rw-p 00000000 00:00 0
  [stack:10305]
7f2970000000-7f2970022000 rw-p 00000000 00:00 0
7f2970022000-7f2974000000 ---p 00000000 00:00 0
7f29746d5000-7f29746d6000 ---p 00000000 00:00 0
7f29746d6000-7f2974ed6000 rw-p 00000000 00:00 0
  [stack:10304]
7f2974ed6000-7f2974ed7000 ---p 00000000 00:00 0
7f2974ed7000-7f29756d7000 rw-p 00000000 00:00 0
  [stack:10303]
7f29756d7000-7f29756d8000 ---p 00000000 00:00 0
7f29756d8000-7f2975ed8000 rw-p 00000000 00:00 0
  [stack:10302]
7f2975ed8000-7f2975ed9000 ---p 00000000 00:00 0
7f2975ed9000-7f29766d9000 rw-p 00000000 00:00 0
  [stack:10301]
7f29766d9000-7f29766e9000 r-xp 00000000 08:05 7996945
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstxvimagesink.so
7f29766e9000-7f29768e9000 ---p 00010000 08:05 7996945
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstxvimagesink.so
7f29768e9000-7f29768ea000 r--p 00010000 08:05 7996945
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstxvimagesink.so
7f29768ea000-7f29768eb000 rw-p 00011000 08:05 7996945
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstxvimagesink.so
7f29768eb000-7f29768f3000 r-xp 00000000 08:05 7998512
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstautodetect.so
7f29768f3000-7f2976af2000 ---p 00008000 08:05 7998512
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstautodetect.so
7f2976af2000-7f2976af3000 r--p 00007000 08:05 7998512
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstautodetect.so
7f2976af3000-7f2976af4000 rw-p 00008000 08:05 7998512
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstautodetect.so
7f2976af4000-7f2976b33000 r-xp 00000000 08:05 7478406
  /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2
7f2976b33000-7f2976d33000 ---p 0003f000 08:05 7478406
  /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2
7f2976d33000-7f2976d34000 r--p 0003f000 08:05 7478406
  /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2
7f2976d34000-7f2976d35000 rw-p 00040000 08:05 7478406
  /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2
7f2976d35000-7f2976d45000 rw-p 00000000 00:00 0
7f2976d45000-7f2976d68000 r-xp 00000000 08:05 7478720
  /usr/lib/x86_64-linux-gnu/libv4lconvert.so.0
7f2976d68000-7f2976f68000 ---p 00023000 08:05 7478720
  /usr/lib/x86_64-linux-gnu/libv4lconvert.so.0
7f2976f68000-7f2976f6a000 r--p 00023000 08:05 7478720
  /usr/lib/x86_64-linux-gnu/libv4lconvert.so.0
7f2976f6a000-7f2976f6b000 rw-p 00025000 08:05 7478720
  /usr/lib/x86_64-linux-gnu/libv4lconvert.so.0
7f2976f6b000-7f2976fbd000 rw-p 00000000 00:00 0
7f2976fbd000-7f2976fc5000 r-xp 00000000 08:05 7478351
  /usr/lib/x86_64-linux-gnu/libgudev-1.0.so.0.1.1
7f2976fc5000-7f29771c5000 ---p 00008000 08:05 7478351
  /usr/lib/x86_64-linux-gnu/libgudev-1.0.so.0.1.1
7f29771c5000-7f29771c6000 r--p 00008000 08:05 7478351
  /usr/lib/x86_64-linux-gnu/libgudev-1.0.so.0.1.1
7f29771c6000-7f29771c7000 rw-p 00009000 08:05 7478351
  /usr/lib/x86_64-linux-gnu/libgudev-1.0.so.0.1.1
7f29771c7000-7f29771cf000 r-xp 00000000 08:05 7478719
  /usr/lib/x86_64-linux-gnu/libv4l2.so.0
7f29771cf000-7f29773ce000 ---p 00008000 08:05 7478719
  /usr/lib/x86_64-linux-gnu/libv4l2.so.0
7f29773ce000-7f29773cf000 r--p 00007000 08:05 7478719
  /usr/lib/x86_64-linux-gnu/libv4l2.so.0
7f29773cf000-7f29773d3000 rw-p 00008000 08:05 7478719
  /usr/lib/x86_64-linux-gnu/libv4l2.so.0
7f29773d3000-7f29773d8000 r-xp 00000000 08:05 7477911
  /usr/lib/x86_64-linux-gnu/libXv.so.1.0.0
7f29773d8000-7f29775d7000 ---p 00005000 08:05 7477911
  /usr/lib/x86_64-linux-gnu/libXv.so.1.0.0
7f29775d7000-7f29775d8000 r--p 00004000 08:05 7477911
  /usr/lib/x86_64-linux-gnu/libXv.so.1.0.0
7f29775d8000-7f29775d9000 rw-p 00005000 08:05 7477911
  /usr/lib/x86_64-linux-gnu/libXv.so.1.0.0
7f29775d9000-7f29775fe000 r-xp 00000000 08:05 7478309
  /usr/lib/x86_64-linux-gnu/libgstcontroller-0.10.so.0.30.0
7f29775fe000-7f29777fd000 ---p 00025000 08:05 7478309
  /usr/lib/x86_64-linux-gnu/libgstcontroller-0.10.so.0.30.0
7f29777fd000-7f29777fe000 r--p 00024000 08:05 7478309
  /usr/lib/x86_64-linux-gnu/libgstcontroller-0.10.so.0.30.0
7f29777fe000-7f29777ff000 rw-p 00025000 08:05 7478309
  /usr/lib/x86_64-linux-gnu/libgstcontroller-0.10.so.0.30.0
7f29777ff000-7f2977800000 ---p 00000000 00:00 0
7f2977800000-7f2978000000 rw-p 00000000 00:00 0
  [stack:10300]
7f2978000000-7f2978021000 rw-p 00000000 00:00 0
7f2978021000-7f297c000000 ---p 00000000 00:00 0
7f297c012000-7f297c038000 rw-s 00000000 00:04 7569422
  /SYSV00000000 (deleted)
7f297c038000-7f297c05e000 rw-s 00000000 00:04 7536653
  /SYSV00000000 (deleted)
7f297c05e000-7f297c084000 rw-s 00000000 00:04 7503884
  /SYSV00000000 (deleted)
7f297c084000-7f297c0aa000 rw-s 00000000 00:04 7471115
  /SYSV00000000 (deleted)
7f297c0aa000-7f297c0d0000 rw-s 00000000 00:04 7438346
  /SYSV00000000 (deleted)
7f297c0d0000-7f297c0f6000 rw-s 00000000 00:04 7405577
  /SYSV00000000 (deleted)
7f297c0f6000-7f297c11c000 rw-s 00000000 00:04 7372808
  /SYSV00000000 (deleted)
7f297c11c000-7f297c142000 rw-s 00000000 00:04 7340039
  /SYSV00000000 (deleted)
7f297c142000-7f297c163000 r-xp 00000000 08:05 7998691
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideo4linux2.so
7f297c163000-7f297c362000 ---p 00021000 08:05 7998691
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideo4linux2.so
7f297c362000-7f297c363000 r--p 00020000 08:05 7998691
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideo4linux2.so
7f297c363000-7f297c364000 rw-p 00021000 08:05 7998691
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideo4linux2.so
7f297c364000-7f297c36e000 r-xp 00000000 08:05 7997165
  /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so
7f297c36e000-7f297c56d000 ---p 0000a000 08:05 7997165
  /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so
7f297c56d000-7f297c56e000 r--p 00009000 08:05 7997165
  /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so
7f297c56e000-7f297c56f000 rw-p 0000a000 08:05 7997165
  /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so
7f297c56f000-7f297c570000 ---p 00000000 00:00 0
7f297c570000-7f297cd70000 rw-p 00000000 00:00 0
  [stack:10299]
7f297cd70000-7f297cd8b000 r-xp 00000000 08:05 7997199
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideoscale.so
7f297cd8b000-7f297cf8b000 ---p 0001b000 08:05 7997199
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideoscale.so
7f297cf8b000-7f297cf8c000 r--p 0001b000 08:05 7997199
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideoscale.so
7f297cf8c000-7f297cf8d000 rw-p 0001c000 08:05 7997199
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideoscale.so
7f297cf8d000-7f297cf8e000 rw-p 00000000 00:00 0
7f297cf8e000-7f297cfdf000 r-xp 00000000 08:05 7997218
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstffmpegcolorspace.so
7f297cfdf000-7f297d1de000 ---p 00051000 08:05 7997218
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstffmpegcolorspace.so
7f297d1de000-7f297d1df000 r--p 00050000 08:05 7997218
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstffmpegcolorspace.so
7f297d1df000-7f297d1e1000 rw-p 00051000 08:05 7997218
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstffmpegcolorspace.so
7f297d1e1000-7f297d1e2000 rw-p 00000000 00:00 0
7f297d1e2000-7f297d1e9000 r-xp 00000000 08:05 7997209
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideorate.so
7f297d1e9000-7f297d3e8000 ---p 00007000 08:05 7997209
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideorate.so
7f297d3e8000-7f297d3e9000 r--p 00006000 08:05 7997209
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideorate.so
7f297d3e9000-7f297d3ea000 rw-p 00007000 08:05 7997209
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstvideorate.so
7f297d3ea000-7f297d42b000 r-xp 00000000 08:05 7998529
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstcoreelements.so
7f297d42b000-7f297d62a000 ---p 00041000 08:05 7998529
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstcoreelements.so
7f297d62a000-7f297d62b000 r--p 00040000 08:05 7998529
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstcoreelements.so
7f297d62b000-7f297d62d000 rw-p 00041000 08:05 7998529
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstcoreelements.so
7f297d62d000-7f297d634000 r-xp 00000000 08:05 7998582
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstgsettingselements.so
7f297d634000-7f297d833000 ---p 00007000 08:05 7998582
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstgsettingselements.so
7f297d833000-7f297d834000 r--p 00006000 08:05 7998582
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstgsettingselements.so
7f297d834000-7f297d835000 rw-p 00007000 08:05 7998582
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstgsettingselements.so
7f297d835000-7f297d840000 r-xp 00000000 08:05 7475445
  /usr/lib/x86_64-linux-gnu/libgstriff-0.10.so.0.25.0
7f297d840000-7f297da40000 ---p 0000b000 08:05 7475445
  /usr/lib/x86_64-linux-gnu/libgstriff-0.10.so.0.25.0
7f297da40000-7f297da41000 r--p 0000b000 08:05 7475445
  /usr/lib/x86_64-linux-gnu/libgstriff-0.10.so.0.25.0
7f297da41000-7f297da42000 rw-p 0000c000 08:05 7475445
  /usr/lib/x86_64-linux-gnu/libgstriff-0.10.so.0.25.0
7f297da42000-7f297da66000 r-xp 00000000 08:05 7998513
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstavi.so
7f297da66000-7f297dc66000 ---p 00024000 08:05 7998513
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstavi.so
7f297dc66000-7f297dc67000 r--p 00024000 08:05 7998513
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstavi.so
7f297dc67000-7f297dc68000 rw-p 00025000 08:05 7998513
  /usr/lib/x86_64-linux-gnu/gstreamer-0.10/libgstavi.so
7f297dc68000-Stacktrace:

  at (wrapper managed-to-native) Gtk.Application.gtk_main () <0xffffffff>
  at Gtk.Application.Run () <0x0000b>
  at ChronoJump..ctor (string[]) <0x00173>
  at ChronoJump.Main (string[]) <0x00143>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void_object
(object,intptr,intptr,intptr) <0xffffffff>

Native stacktrace:

    mono() [0x4961e9]
    /lib/x86_64-linux-gnu/libpthread.so.0(+0xfcb0) [0x7f29b0302cb0]
    /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x35) [0x7f29aff6a425]
    /lib/x86_64-linux-gnu/libc.so.6(abort+0x17b) [0x7f29aff6db8b]
    /lib/x86_64-linux-gnu/libc.so.6(+0x7439e) [0x7f29affa839e]
    /lib/x86_64-linux-gnu/libc.so.6(+0x7eb96) [0x7f29affb2b96]
    /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0(gdk_region_intersect+0x72)
[0x7f29a7d81942]
    /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0(+0x3ddff) [0x7f29a7d8bdff]
    /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0(gdk_window_process_all_updates+0x131)
[0x7f29a7d8e201]
    /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0(+0xb8bb1) [0x7f29ac1b2bb1]
    /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0(+0x1de77) [0x7f29a7d6be77]
    /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_main_context_dispatch+0x135)
[0x7f29a5fc7ab5]
    /lib/x86_64-linux-gnu/libglib-2.0.so.0(+0x47de8) [0x7f29a5fc7de8]
    /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_main_loop_run+0x72)
[0x7f29a5fc81e2]
    /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0(gtk_main+0xa7)
[0x7f29ac22dc77]
    [0x40923f75]

Debug info from gdb:

Could not attach to process.  If your uid matches the uid of the target
process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try
again as the root user.  For more details, see /etc/sysctl.d/10-ptrace.conf
ptrace: Operation not permitted.
No threads.

=================================================================
Got a SIGABRT while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries
used by your application.
=================================================================

Aborted