On Wed, 30 Mar 2016 12:01:58 +0530 Vikas Patil <vikasmpa...@gmail.com> wrote:
> Dear all, > > I am observing "Segmentation fault" with below mentioned back-trace > while playing video (loop back mode )and continuously pressing home > button on target (which brings video screen to home screen of HMI). > > Printing the locals shows null pointer deference (i.e. line 46, print > elm->next, wl_list_insert, /wayland-1.8.1/src/wayland-util.c:46 ) > > Am I hitting some known issue with wayland/weston? How should I debug > this further and find the root cause if it is not known issue? Could > you guys please provide input/suggestion on finding the root cause? > > I am on wayland/weston 1.8.0 and using i.MX6/Linux3.14.28. Test > application is based on gstreamer1.0 and uses wayland based > “imxeglvivsink“ as video sink plug-in. Home button is a gpio mapped to > KEY_HOME as standard keyboard and uses input stack as it is from > wayland/weston and libinput. > > > Backtrace: > warning: Unable to find libthread_db matching inferior's thread > library, thread debugging will not be available. > warning: Unable to find libthread_db matching inferior's thread > library, thread debugging will not be available. > Core was generated by `./testVideoPlayer'. > Program terminated with signal SIGSEGV, Segmentation fault. > > #0 wl_list_insert (list=0x1, elm=0x1802660, elm@entry=0x16c) at > /usr/src/debug/wayland/1.8.1-r0/wayland-1.8.1/src/wayland-util.c:46 > > 46 elm->next = list->next; > > (gdb) bt > > #0 wl_list_insert (list=0x1, elm=0x1802660, elm@entry=0x16c) at > /usr/src/debug/wayland/1.8.1-r0/wayland-1.8.1/src/wayland-util.c:46 > > #1 0x75c412c8 in queue_event (len=1975783972, display=0x180116c) at > /usr/src/debug/wayland/1.8.1-r0/wayland-1.8.1/src/wayland-client.c:1122 > > #2 read_events (display=<optimized out>) at > /usr/src/debug/wayland/1.8.1-r0/wayland-1.8.1/src/wayland-client.c:1207 > > #3 0x75c42030 in wl_display_dispatch_queue > (display=display@entry=0x76036800, queue=queue@entry=0x760005a8) at > /usr/src/debug/wayland/1.8.1-r0/wayland-1.8.1/src/wayland-client.c:1579 > > #4 0x75c42290 in wl_display_roundtrip_queue (display=0x76036800, > queue=0x760005a8) at > /usr/src/debug/wayland/1.8.1-r0/wayland-1.8.1/src/wayland-client.c:982 > > #5 0x75d56cb4 in wl_egl_window_destroy (window=0x1801104) at > gc_egl_platform.c:779 > > #6 0x75d7ab44 in gst_imx_egl_viv_sink_egl_platform_shutdown_window ( > platform=0x76016f00) at ../src/eglvivsink/egl_platform_wayland.c:990 > > #7 0x75d77e68 in gst_imx_egl_viv_sink_gles2_renderer_thread ( > thread_data=<optimized out>) at ../src/eglvivsink/gles2_renderer.c:227 Hi, this looks very much like a threading issue in gst imx egl viv sink or perhaps in the proprietary EGL implementation. Being random instead of deterministically every time you press the button also hints to a race. Note, that the code you are looking at is not Weston, it is some application. I don't think this has anything to do with Weston or Wayland really... Unless this happens to be the case of multiple threads racing between setting up queues and listeners for a wl_callback vs. receiving and dispatching events: https://bugs.freedesktop.org/show_bug.cgi?id=91768 However, there are things that make looking into your issue very difficult for upstream: - old weston and wayland - gstreamer sink written for a proprietary software platform - proprietary EGL implementation - use of IVI - use of applications we cannot have the sources for (I presume) IOW, it doesn't look like there would be any way for us to reproduce the issue to have a look into. Thanks, pq
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