On pc Debian testing x86-64 with LO 6.4.1.1 + gtk3, I don't reproduce this.

Could you give a try at:
https://wiki.documentfoundation.org/QA/FirstSteps
?

If you still reproduce this, could you attach the example file of words? Does it contains plain ascii or special/accentuated characters?

Finally, oi, which Linux distrib are you, could you give a try to a more recent LO version since 6.2 branch is EOL? (if Ubuntu, you can try LO ppa).

Created attachment 158189 [details]
Example text file

It's a very simple text file that I'm importing. It has unix file ending and just ASCII codes, I've tried other files and the same happens.

Actually I see the crash happens even if, after selecting the file, I cancel the import from the window where I'm asked in what format the CSV file is etc.

I'm in Fedora 30 with KDE (plasmashell 5.15.5, dolphin 19.08.3). As a first step I've tried updating to 6.3.4.2-2.fc31 and the same happened:

Fatal exception: Signal 11
Stack:
/usr/lib64/libreoffice/program/libuno_sal.so.3(+0x3d373)[0x7f034d67d373]
/usr/lib64/libreoffice/program/libuno_sal.so.3(+0x3d4ea)[0x7f034d67d4ea]
/lib64/libc.so.6(+0x37ec0)[0x7f034d377ec0]
/usr/lib64/libreoffice/program/../program/libfps_officelo.so(+0x52c94)[0x7f0320b0ac94]
/usr/lib64/libreoffice/program/libsvtlo.so(+0x1d083d)[0x7f034ac3083d]
/usr/lib64/libreoffice/program/libvcllo.so(_ZN9SvImpLBox15MouseButtonDownERK10MouseEvent+0x1e8)[0x7f0349f2a1b8]
/usr/lib64/libreoffice/program/libvcllo.so(+0x421255)[0x7f0349e21255]
/usr/lib64/libreoffice/program/libvcllo.so(+0x42171e)[0x7f0349e2171e]
/usr/lib64/libreoffice/program/libvcllo.so(+0x422273)[0x7f0349e22273]
/usr/lib64/libreoffice/program/libvclplug_gtk3lo.so(+0x14b089)[0x7f033df33089]
/usr/lib64/libreoffice/program/libvclplug_gtk3lo.so(+0x14c75d)[0x7f033df3475d]
/lib64/libgtk-3.so.0(+0x3e65cb)[0x7f033da665cb]
/lib64/libgobject-2.0.so.0(g_closure_invoke+0x1b2)[0x7f0346573742]
/lib64/libgobject-2.0.so.0(+0x274f4)[0x7f03465874f4]
/lib64/libgobject-2.0.so.0(g_signal_emit_valist+0x571)[0x7f034658f9c1]
/lib64/libgobject-2.0.so.0(g_signal_emit+0x93)[0x7f0346590973]
/lib64/libgtk-3.so.0(+0x391153)[0x7f033da11153]
/lib64/libgtk-3.so.0(+0x24cd08)[0x7f033d8ccd08]
/lib64/libgtk-3.so.0(gtk_main_do_event+0x85b)[0x7f033d8cef1b]
/lib64/libgdk-3.so.0(+0x3cf79)[0x7f033d5b4f79]
/lib64/libgdk-3.so.0(+0x70086)[0x7f033d5e8086]
/lib64/libglib-2.0.so.0(g_main_context_dispatch+0x15d)[0x7f0346487ecd]
/lib64/libglib-2.0.so.0(+0x50260)[0x7f0346488260]
/lib64/libglib-2.0.so.0(g_main_loop_run+0xc3)[0x7f0346488593]
/usr/lib64/libreoffice/program/libvclplug_gtk3lo.so(+0xde699)[0x7f033dec6699]
/usr/lib64/libreoffice/program/libscuilo.so(+0xc13d2)[0x7f03211613d2]
/usr/lib64/libreoffice/program/../program/libsclo.so(_ZN14ScTabViewShell12ExecuteTableER10SfxRequest+0x1882)[0x7f0323336742]
/usr/lib64/libreoffice/program/libsfxlo.so(+0x2b07f6)[0x7f034c1187f6]
/usr/lib64/libreoffice/program/libsfxlo.so(_ZN13SfxDispatcher8Execute_ER8SfxShellRK7SfxSlotR10SfxRequest11SfxCallMode+0x11d)[0x7f034c118dad]
/usr/lib64/libreoffice/program/libsfxlo.so(+0x2ad73e)[0x7f034c11573e]
/usr/lib64/libreoffice/program/libsfxlo.so(+0x304e74)[0x7f034c16ce74]
/usr/lib64/libreoffice/program/libsfxlo.so(+0x305433)[0x7f034c16d433]
/usr/lib64/libreoffice/program/../program/libfwklo.so(+0x1e4384)[0x7f0337efc384]
/usr/lib64/libreoffice/program/libvcllo.so(_ZN4Menu6SelectEv+0x74)[0x7f0349dac194]
/usr/lib64/libreoffice/program/libvcllo.so(+0x3aede0)[0x7f0349daede0]
/usr/lib64/libreoffice/program/libvcllo.so(_ZN9PopupMenu7ExecuteEPN3vcl6WindowERKN5tools9RectangleE14PopupMenuFlags+0x73)[0x7f0349daf4b3]
/usr/lib64/libreoffice/program/libvcllo.so(_ZN9PopupMenu7ExecuteEPN3vcl6WindowERK5Point+0x3f)[0x7f0349daf57f]
/usr/lib64/libreoffice/program/libsfxlo.so(_ZN13SfxDispatcher12ExecutePopupERKN3rtl8OUStringEPN3vcl6WindowEPK5Point+0xec6)[0x7f034c11f366]
/usr/lib64/libreoffice/program/../program/libsclo.so(+0xcb3b4b)[0x7f0323303b4b]
/usr/lib64/libreoffice/program/libvcllo.so(+0x41e940)[0x7f0349e1e940]
/usr/lib64/libreoffice/program/libvcllo.so(+0x4214d1)[0x7f0349e214d1]
/usr/lib64/libreoffice/program/libvcllo.so(+0x42171e)[0x7f0349e2171e]
/usr/lib64/libreoffice/program/libvcllo.so(+0x422273)[0x7f0349e22273]
/usr/lib64/libreoffice/program/libvclplug_gtk3lo.so(+0x14b089)[0x7f033df33089]
/usr/lib64/libreoffice/program/libvclplug_gtk3lo.so(+0x14c75d)[0x7f033df3475d]
/lib64/libgtk-3.so.0(+0x3e65cb)[0x7f033da665cb]
/lib64/libgobject-2.0.so.0(g_closure_invoke+0x1b2)[0x7f0346573742]
/lib64/libgobject-2.0.so.0(+0x274f4)[0x7f03465874f4]
/lib64/libgobject-2.0.so.0(g_signal_emit_valist+0x571)[0x7f034658f9c1]
/lib64/libgobject-2.0.so.0(g_signal_emit+0x93)[0x7f0346590973]
/lib64/libgtk-3.so.0(+0x391153)[0x7f033da11153]
/lib64/libgtk-3.so.0(+0x24cd08)[0x7f033d8ccd08]
/lib64/libgtk-3.so.0(gtk_main_do_event+0x85b)[0x7f033d8cef1b]
/lib64/libgdk-3.so.0(+0x3cf79)[0x7f033d5b4f79]
/lib64/libgdk-3.so.0(+0x70086)[0x7f033d5e8086]
/lib64/libglib-2.0.so.0(g_main_context_dispatch+0x15d)[0x7f0346487ecd]
/lib64/libglib-2.0.so.0(+0x50260)[0x7f0346488260]
/lib64/libglib-2.0.so.0(g_main_context_iteration+0x33)[0x7f0346488303]
/usr/lib64/libreoffice/program/libvclplug_gtk3lo.so(+0xd530c)[0x7f033debd30c]
/usr/lib64/libreoffice/program/libvcllo.so(+0x6c4592)[0x7f034a0c4592]
/usr/lib64/libreoffice/program/libvcllo.so(_ZN11Application7ExecuteEv+0x45)[0x7f034a0c6565]
/usr/lib64/libreoffice/program/libsofficeapp.so(+0x3b0d1)[0x7f034d5930d1]
/usr/lib64/libreoffice/program/libvcllo.so(_Z10ImplSVMainv+0x51)[0x7f034a0cd291]
/usr/lib64/libreoffice/program/libsofficeapp.so(soffice_main+0x97)[0x7f034d5b9207]
/usr/lib64/libreoffice/program/soffice.bin(+0x10c0)[0x561dc63f90c0]
/lib64/libc.so.6(__libc_start_main+0xf3)[0x7f034d363f43]
/usr/lib64/libreoffice/program/soffice.bin(+0x10fe)[0x561dc63f90fe]

I can't reproduce it in

Version: 7.0.0.0.alpha0+
Build ID: 828504974d70111e4a35b31d579cf42fe660a660
CPU threads: 4; OS: Linux 4.19; UI render: default; VCL: gtk3; 
Locale: en-US (en_US.UTF-8); UI-Language: en-US
Calc: threaded

@Nemo, Does it crash if you launch LibreOffice from command line with 'SAL_USE_VCLPLUGIN=gen soffice' ?

(In reply to Xisco Faulí from comment #5)
> @Nemo, Does it crash if you launch LibreOffice from command line with
> 'SAL_USE_VCLPLUGIN=gen soffice' ?

Thank you for the suggestion! Yes it does, with a different error (just "Application Error" and no stack trace).

As next steps I'll try rebooting (sometimes KDE/Plasma upgrades cause weird temporary errors) and removing my user profile, then the upgrade to a rawhide or master version. Sorry for the confusion if I didn't follow the best procedure so far.

maybe related to:

Dialog "Insert sheet from file" in Calc hangs at "Insert Sheet" dialog for LO version >6.2
https://bugs.documentfoundation.org/show_bug.cgi?id=129082

Can you try with LO 6.3.5 ?

Dear Nemo_bis,

Please read this message in its entirety before proceeding.

Your bug report is being closed as INSUFFICIENTDATA due to inactivity and
a lack of information which is needed in order to accurately
reproduce and confirm the problem. We encourage you to retest
your bug against the latest release. If the issue is still
present in the latest stable release, we need the following
information (please ignore any that you've already provided):

a) Provide details of your system including your operating
   system and the latest version of LibreOffice that you have
   confirmed the bug to be present

b) Provide easy to reproduce steps – the simpler the better

c) Provide any test case(s) which will help us confirm the problem

d) Provide screenshots of the problem if you think it might help

e) Read all comments and provide any requested information

Once all of this is done, please set the bug back to UNCONFIRMED
and we will attempt to reproduce the issue. Please do not:

a) respond via email 

b) update the version field in the bug or any of the other details
   on the top section of our bug tracker

Warm Regards,
QA Team

MassPing-NeedInfo-FollowUp