kitty segfaults when selecting in diff kitten

[SolitudeSF]

if you scroll downwards and start selecting text upwards, after few scrolls kitty segfaults.

[kovidgoyal]

Can you post a backtrace of the crash?

On most linux distributions, it ouwld require:

make debug
cause crash
echo bt | coredumpctl gdb

I cannot reproduce with your description, on master, steps I tried:

1. Run diff kitten
2. scroll down
3. drag upwards with the mouse

Note that the diff kitten does not currently implement mouse
integration, so dragging withthe mouse will not cause the kitten to
scroll upwards.

[SolitudeSF]

ah, by selecting text upwards i meant selecting it and scrolling upwards with mouse wheel.

[kovidgoyal]

You mean yo uare holdingdown the left mouse button and usingthe wheel at
the same time?

[SolitudeSF]

yep

[SolitudeSF]

also it works fails reliably when starting selection from the last line

[kovidgoyal]

I cant get it to crash on my system running from aster while doing that.
Also I'm not sure I understand why you are doing that. You cannot select
multiple screenfuls of text by doing it. For that mouse support has to
be added to the kitten, which is on my TODO list

[kovidgoyal]

A backtrace from the crash would help.

[SolitudeSF]

hmm, im having some problems with that, maybe because of my weird setup. i have core file generated, but doing echo bt | coredumpctl gdb results in

Failed to acquire bus: No such file or directory
No journal files were found.
No match found.

im pretty clueless in debugging

also segfault occurs on mouse button up

[kovidgoyal]

see https://stackoverflow.com/questions/5745215/getting-stacktrace-from-core-dump

[SolitudeSF]

uhh, if i understand correctly, i ran gdb python3 core.
bt gives this

#0  0x00007f3b74cbf038 in xlimit_for_line (line=0x7f3b73236750) at /home/solitude/git/kitty/kitty/screen.c:1564
#1  text_for_selection (self=0x7f3b3a782010, a=<optimized out>) at /home/solitude/git/kitty/kitty/screen.c:1968
#2  0x00007f3b75be7edf in _PyCFunction_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#3  0x00007f3b75c60769 in ?? () from /usr/lib/libpython3.6m.so.1.0
#4  0x00007f3b75c628bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#5  0x00007f3b75c5f873 in ?? () from /usr/lib/libpython3.6m.so.1.0
#6  0x00007f3b75c60625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#7  0x00007f3b75c628bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#8  0x00007f3b75c5f873 in ?? () from /usr/lib/libpython3.6m.so.1.0
#9  0x00007f3b75c682fb in _PyFunction_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#10 0x00007f3b75ba0081 in _PyObject_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#11 0x00007f3b75ba02ec in _PyObject_Call_Prepend () from /usr/lib/libpython3.6m.so.1.0
#12 0x00007f3b75b9ffd9 in _PyObject_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#13 0x00007f3b75ba0bb8 in _PyObject_CallMethod_SizeT () from /usr/lib/libpython3.6m.so.1.0
#14 0x00007f3b74cc5acf in screen_update_selection (self=0x7f3b3a782010, x=<optimized out>, y=<optimized out>, ended=ended@entry=true) at /home/solitude/git/kitty/kitty/screen.c:2143
#15 0x00007f3b74cd5dd4 in update_drag (modifiers=0, is_release=true, w=<optimized out>, from_button=true) at /home/solitude/git/kitty/kitty/mouse.c:169
#16 mouse_event (button=button@entry=0, modifiers=modifiers@entry=0, action=<optimized out>, action@entry=0) at /home/solitude/git/kitty/kitty/mouse.c:534
#17 0x00007f3b74cf926b in mouse_button_callback (w=0x562cbcb3e870, button=0, action=0, mods=0) at /home/solitude/git/kitty/kitty/glfw.c:222
#18 0x00007f3b731af0e4 in _glfwInputMouseClick (window=<optimized out>, button=button@entry=0, action=action@entry=0, mods=<optimized out>) at /home/solitude/git/kitty/glfw/input.c:311
#19 0x00007f3b731badc3 in processEvent (event=event@entry=0x7ffe21ca6ca0) at /home/solitude/git/kitty/glfw/x11_window.c:1267
#20 0x00007f3b731bb64c in dispatch_x11_queued_events () at /home/solitude/git/kitty/glfw/x11_window.c:2508
#21 _glfwDispatchX11Events () at /home/solitude/git/kitty/glfw/x11_window.c:2523
#22 0x00007f3b731bb785 in handleEvents (timeout=<optimized out>) at /home/solitude/git/kitty/glfw/x11_window.c:66
#23 0x00007f3b731bb7b4 in _glfwPlatformWaitEvents () at /home/solitude/git/kitty/glfw/x11_window.c:2555
#24 0x00007f3b731b65a5 in _glfwPlatformRunMainLoop (tick_callback=0x7f3b74d2da2a <process_global_state>, data=0x7f3b72a0a030) at /home/solitude/git/kitty/glfw/main_loop.h:30
#25 0x00007f3b731ae849 in glfwRunMainLoop (callback=<optimized out>, data=<optimized out>) at /home/solitude/git/kitty/glfw/init.c:342
#26 0x00007f3b74cfa64c in run_main_loop (cb=cb@entry=0x7f3b74d2da2a <process_global_state>, cb_data=cb_data@entry=0x7f3b72a0a030) at /home/solitude/git/kitty/kitty/glfw.c:1136
#27 0x00007f3b74d2a6e6 in main_loop (self=0x7f3b72a0a030, a=<optimized out>) at /home/solitude/git/kitty/kitty/child-monitor.c:955
#28 0x00007f3b75be7edf in _PyCFunction_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#29 0x00007f3b75c60769 in ?? () from /usr/lib/libpython3.6m.so.1.0
#30 0x00007f3b75c628bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#31 0x00007f3b75c6029a in ?? () from /usr/lib/libpython3.6m.so.1.0
#32 0x00007f3b75c60413 in ?? () from /usr/lib/libpython3.6m.so.1.0
#33 0x00007f3b75c60625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#34 0x00007f3b75c628bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#35 0x00007f3b75c6029a in ?? () from /usr/lib/libpython3.6m.so.1.0
#36 0x00007f3b75c60413 in ?? () from /usr/lib/libpython3.6m.so.1.0
#37 0x00007f3b75c60625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#38 0x00007f3b75c628bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#39 0x00007f3b75c5f873 in ?? () from /usr/lib/libpython3.6m.so.1.0
#40 0x00007f3b75c60625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#41 0x00007f3b75c628bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#42 0x00007f3b75c5f873 in ?? () from /usr/lib/libpython3.6m.so.1.0
#43 0x00007f3b75c60625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#44 0x00007f3b75c628bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#45 0x00007f3b75c5f873 in ?? () from /usr/lib/libpython3.6m.so.1.0
#46 0x00007f3b75c60625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#47 0x00007f3b75c628bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#48 0x00007f3b75c6029a in ?? () from /usr/lib/libpython3.6m.so.1.0
#49 0x00007f3b75c607ce in PyEval_EvalCodeEx () from /usr/lib/libpython3.6m.so.1.0
#50 0x00007f3b75c607fb in PyEval_EvalCode () from /usr/lib/libpython3.6m.so.1.0
--Type <RET> for more, q to quit, c to continue without paging--
#51 0x00007f3b75c5d6ad in ?? () from /usr/lib/libpython3.6m.so.1.0
#52 0x00007f3b75be7f2b in _PyCFunction_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#53 0x00007f3b75c60769 in ?? () from /usr/lib/libpython3.6m.so.1.0
#54 0x00007f3b75c628bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#55 0x00007f3b75c6029a in ?? () from /usr/lib/libpython3.6m.so.1.0
#56 0x00007f3b75c607ce in PyEval_EvalCodeEx () from /usr/lib/libpython3.6m.so.1.0
#57 0x00007f3b75c607fb in PyEval_EvalCode () from /usr/lib/libpython3.6m.so.1.0
#58 0x00007f3b75c89b94 in ?? () from /usr/lib/libpython3.6m.so.1.0
#59 0x00007f3b75c8c0c1 in PyRun_FileExFlags () from /usr/lib/libpython3.6m.so.1.0
#60 0x00007f3b75c8c22d in PyRun_SimpleFileExFlags () from /usr/lib/libpython3.6m.so.1.0
#61 0x00007f3b75ca2ee2 in Py_Main () from /usr/lib/libpython3.6m.so.1.0
#62 0x0000562cbafee238 in main ()

[kovidgoyal]

Is that with kitty master or some other version, the line numbers dont match current source code.

[SolitudeSF]

well, i just cloned the git repo, you can see it in the paths

[SolitudeSF]

okay, i think i ran it wrong. here is new backtrace.

#0  0x00007ff21e2a4038 in xlimit_for_line (line=0x7ff21cb05660) at /home/solitude/git/kitty/kitty/screen.c:1564
#1  text_for_selection (self=0x7ff1e7cd3010, a=<optimized out>) at /home/solitude/git/kitty/kitty/screen.c:1968
#2  0x00007ff21f20cedf in _PyCFunction_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#3  0x00007ff21f285769 in ?? () from /usr/lib/libpython3.6m.so.1.0
#4  0x00007ff21f2878bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#5  0x00007ff21f284873 in ?? () from /usr/lib/libpython3.6m.so.1.0
#6  0x00007ff21f285625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#7  0x00007ff21f2878bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#8  0x00007ff21f284873 in ?? () from /usr/lib/libpython3.6m.so.1.0
#9  0x00007ff21f28d2fb in _PyFunction_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#10 0x00007ff21f1c5081 in _PyObject_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#11 0x00007ff21f1c52ec in _PyObject_Call_Prepend () from /usr/lib/libpython3.6m.so.1.0
#12 0x00007ff21f1c4fd9 in _PyObject_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#13 0x00007ff21f1c5bb8 in _PyObject_CallMethod_SizeT () from /usr/lib/libpython3.6m.so.1.0
#14 0x00007ff21e2aaacf in screen_update_selection (self=0x7ff1e7cd3010, x=<optimized out>, y=<optimized out>, 
    ended=ended@entry=true) at /home/solitude/git/kitty/kitty/screen.c:2143
#15 0x00007ff21e2badd4 in update_drag (modifiers=0, is_release=true, w=<optimized out>, from_button=true)
    at /home/solitude/git/kitty/kitty/mouse.c:169
#16 mouse_event (button=button@entry=0, modifiers=modifiers@entry=0, action=<optimized out>, action@entry=0)
    at /home/solitude/git/kitty/kitty/mouse.c:534
#17 0x00007ff21e2de26b in mouse_button_callback (w=0x56007ad71b10, button=0, action=0, mods=0)
    at /home/solitude/git/kitty/kitty/glfw.c:222
#18 0x00007ff21c5e70e4 in _glfwInputMouseClick (window=<optimized out>, button=button@entry=0, action=action@entry=0, 
    mods=<optimized out>) at /home/solitude/git/kitty/glfw/input.c:311
#19 0x00007ff21c5f2dc3 in processEvent (event=event@entry=0x7ffd06cd4940)
    at /home/solitude/git/kitty/glfw/x11_window.c:1267
#20 0x00007ff21c5f364c in dispatch_x11_queued_events () at /home/solitude/git/kitty/glfw/x11_window.c:2508
#21 _glfwDispatchX11Events () at /home/solitude/git/kitty/glfw/x11_window.c:2523
#22 0x00007ff21c5f3785 in handleEvents (timeout=<optimized out>) at /home/solitude/git/kitty/glfw/x11_window.c:66
#23 0x00007ff21c5f37b4 in _glfwPlatformWaitEvents () at /home/solitude/git/kitty/glfw/x11_window.c:2555
#24 0x00007ff21c5ee5a5 in _glfwPlatformRunMainLoop (tick_callback=0x7ff21e312a2a <process_global_state>, 
    data=0x7ff21c85c990) at /home/solitude/git/kitty/glfw/main_loop.h:30
#25 0x00007ff21c5e6849 in glfwRunMainLoop (callback=<optimized out>, data=<optimized out>)
    at /home/solitude/git/kitty/glfw/init.c:342
#26 0x00007ff21e2df64c in run_main_loop (cb=cb@entry=0x7ff21e312a2a <process_global_state>, 
    cb_data=cb_data@entry=0x7ff21c85c990) at /home/solitude/git/kitty/kitty/glfw.c:1136
#27 0x00007ff21e30f6e6 in main_loop (self=0x7ff21c85c990, a=<optimized out>)
    at /home/solitude/git/kitty/kitty/child-monitor.c:955
#28 0x00007ff21f20cedf in _PyCFunction_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#29 0x00007ff21f285769 in ?? () from /usr/lib/libpython3.6m.so.1.0
#30 0x00007ff21f2878bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#31 0x00007ff21f28529a in ?? () from /usr/lib/libpython3.6m.so.1.0
#32 0x00007ff21f285413 in ?? () from /usr/lib/libpython3.6m.so.1.0
#33 0x00007ff21f285625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#34 0x00007ff21f2878bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#35 0x00007ff21f28529a in ?? () from /usr/lib/libpython3.6m.so.1.0
#36 0x00007ff21f285413 in ?? () from /usr/lib/libpython3.6m.so.1.0
#37 0x00007ff21f285625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#38 0x00007ff21f2878bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#39 0x00007ff21f284873 in ?? () from /usr/lib/libpython3.6m.so.1.0
#40 0x00007ff21f285625 in ?? () from /usr/lib/libpython3.6m.so.1.0
--Type <RET> for more, q to quit, c to continue without paging--
#41 0x00007ff21f2878bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#42 0x00007ff21f284873 in ?? () from /usr/lib/libpython3.6m.so.1.0
#43 0x00007ff21f285625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#44 0x00007ff21f2878bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#45 0x00007ff21f284873 in ?? () from /usr/lib/libpython3.6m.so.1.0
#46 0x00007ff21f285625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#47 0x00007ff21f2878bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#48 0x00007ff21f28529a in ?? () from /usr/lib/libpython3.6m.so.1.0
#49 0x00007ff21f2857ce in PyEval_EvalCodeEx () from /usr/lib/libpython3.6m.so.1.0
#50 0x00007ff21f2857fb in PyEval_EvalCode () from /usr/lib/libpython3.6m.so.1.0
#51 0x00007ff21f2826ad in ?? () from /usr/lib/libpython3.6m.so.1.0
#52 0x00007ff21f20cf2b in _PyCFunction_FastCallDict () from /usr/lib/libpython3.6m.so.1.0
#53 0x00007ff21f285769 in ?? () from /usr/lib/libpython3.6m.so.1.0
#54 0x00007ff21f2878bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#55 0x00007ff21f28529a in ?? () from /usr/lib/libpython3.6m.so.1.0
#56 0x00007ff21f285413 in ?? () from /usr/lib/libpython3.6m.so.1.0
#57 0x00007ff21f285625 in ?? () from /usr/lib/libpython3.6m.so.1.0
#58 0x00007ff21f2878bb in _PyEval_EvalFrameDefault () from /usr/lib/libpython3.6m.so.1.0
#59 0x00007ff21f28529a in ?? () from /usr/lib/libpython3.6m.so.1.0
#60 0x00007ff21f2857ce in PyEval_EvalCodeEx () from /usr/lib/libpython3.6m.so.1.0
#61 0x00007ff21f1ee626 in ?? () from /usr/lib/libpython3.6m.so.1.0
#62 0x00007ff21f1c4e68 in PyObject_Call () from /usr/lib/libpython3.6m.so.1.0
#63 0x00007ff21f2c6c1d in ?? () from /usr/lib/libpython3.6m.so.1.0
#64 0x00007ff21f2c7d41 in Py_Main () from /usr/lib/libpython3.6m.so.1.0
#65 0x0000560079cc3238 in main ()

[kovidgoyal]

Hmm it's an lnlined function, which is making the backtrace somewhat less helpful. Can you edit lineops.h and remove the inline keyword on line 35 andthen re-build and get a new backtrace.

[SolitudeSF]

uhhh

/home/solitude/git/kitty/kitty/lineops.h:36:1: error: 'xlimit_for_line' defined but not used [-Werror=unused-function]
 xlimit_for_line(Line *line) {