Segfault on terminate with seat input

[WLCIssuesBot]

Issue by crondog Saturday Mar 05, 2016 at 04:17 GMT Originally opened as https://github.com/Cloudef/wlc/issues/134

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I have noticed that if you are moving the mouse while exiting sway cleanly a segfault occurs. This is due to input_event still triggering while wlc is terminating.

[commands.c:2793] find_handler(exit) 0
[main.c:43] [wlc] Terminating wlc...
[main.c:43] [wlc] Terminating compositor...
[main.c:43] [wlc] Output (1) terminated...
[container.c:350] OUTPUT: Destroying output '1'
[main.c:43] [wlc] Removed bsurface from output (1)
[main.c:43] [wlc] Removed output (1)
[main.c:43] [wlc] Compositor terminated...
[log.c:150] Error: Signal 11. Printing backtrace
[log.c:160] Backtrace: sway(error_handler+0xb7) [0x4239ee]
[log.c:160] Backtrace: /usr/lib/libc.so.6(+0x33330) [0x7f8735958330]
[log.c:160] Backtrace: sway() [0x41917e]
[log.c:160] Backtrace: wlc/src/libwlc.so.0(+0x157b7) [0x7f8736ad77b7] seat.c:169
[log.c:160] Backtrace: wlc/src/libwlc.so.0(+0x1b6dd) [0x7f8736add6dd]
[log.c:160] Backtrace: wlc/src/libwlc.so.0(+0x1bf18) [0x7f8736addf18]
[log.c:160] Backtrace: /usr/lib/libwayland-server.so.0(wl_event_loop_dispatch+0xc8) [0x7f87361fe888]
[log.c:160] Backtrace: /usr/lib/libwayland-server.so.0(wl_display_run+0x25) [0x7f87361fcee5]
[log.c:160] Backtrace: wlc/src/libwlc.so.0(wlc_run+0xc3) [0x7f8736aea967]
[log.c:160] Backtrace: sway(main+0x49f) [0x42050b]
[log.c:160] Backtrace: /usr/lib/libc.so.6(__libc_start_main+0xf0) [0x7f8735945710]
[log.c:160] Backtrace: sway(_start+0x29) [0x406b99]

I can think of 2 ways to fix this issue.

• Check for compositor->state.terminating inside input_event
• Have a terminating listener inside seat

I have tried the first option and it works. Would you prefer a terminate listener or do you have a better way?

[WLCIssuesBot]

Comment by Cloudef Saturday Mar 05, 2016 at 11:35 GMT

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What if you move wlc_input_terminate before wlc_compositor_release in wlc.c @ wlc_cleanup? Does this happen under X11 backend?

[WLCIssuesBot]

Comment by crondog Saturday Mar 05, 2016 at 11:40 GMT

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Moving wlc_input_terminate does not help. Yes it is under the X11 backend

[WLCIssuesBot]

Comment by Cloudef Saturday Mar 05, 2016 at 12:10 GMT

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What is exact trace for this? As that track is missing important symbols. If this is under X11 the proper fix is to have the terminating order corrected in compositor.c.

[WLCIssuesBot]

Comment by crondog Saturday Mar 05, 2016 at 12:23 GMT

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[log.c:150] Error: Signal 11. Printing backtrace
[log.c:160] Backtrace: sway(error_handler+0xb7) [0x4239ee]
[log.c:160] Backtrace: /usr/lib/libc.so.6(+0x33330) [0x7f70f2db0330]
[log.c:160] Backtrace: sway() [0x41917e] sway/sway/handlers.c:534
[log.c:160] Backtrace: wlc/src/libwlc.so.0(+0x157b7) [0x7f70f3f2f7b7] src/compositor/seat/seat.c:166
[log.c:160] Backtrace: wlc/src/libwlc.so.0(+0x1b6dd) [0x7f70f3f356dd] /usr/include/wayland-server-core.h:329
[log.c:160] Backtrace: wlc/src/libwlc.so.0(+0x1bf18) [0x7f70f3f35f18] wlc/src/platform/backend/x11.c:224
[log.c:160] Backtrace: /usr/lib/libwayland-server.so.0(wl_event_loop_dispatch+0xc8) [0x7f70f3656888]
[log.c:160] Backtrace: /usr/lib/libwayland-server.so.0(wl_display_run+0x25) [0x7f70f3654ee5]
[log.c:160] Backtrace: wlc/src/libwlc.so.0(wlc_run+0xc3) [0x7f70f3f42967]
[log.c:160] Backtrace: sway(main+0x49f) [0x42050b] sway/sway/main.c:225
[log.c:160] Backtrace: /usr/lib/libc.so.6(__libc_start_main+0xf0) [0x7f70f2d9d710]
[log.c:160] Backtrace: sway(_start+0x29) [0x406b99]