server crash causes a segfault on the client

[a-tour-ist]

Luanti version

Luanti 5.11.0-dev-debug-af3f69642 (Linux)
Using LuaJIT 2.1.1731601260
Built by GCC 14.2
Running on Linux/6.11.11 x86_64
BUILD_TYPE=Debug
RUN_IN_PLACE=1
USE_CURL=1
USE_GETTEXT=1
USE_SOUND=1
STATIC_SHAREDIR="."
STATIC_LOCALEDIR="locale"

Operating system and version

Manjaro Linux

CPU model

Intel© Core™ i7-7600U CPU @ 2.80GHz × 2

GPU model

Intel Corporation HD Graphics 620

Active renderer

4.6/opengl3/SDL

Summary

If the server crashes from a faulty allow_metadata_inventory_* / on_metadata_inventory_, the client that performed the action leading to the server crash will experience a segmentation fault.

Thread 1 "luanti" received signal SIGSEGV, Segmentation fault.
0x0000555557876200 in ?? ()
#0  0x0000555557876200 in ?? ()
#1  0x0000555555996437 in GUIInventoryList::getItemIndexAtPos (this=0x555559275e00, p=...) at /home/tour/Dokumente/yl/minetest/src/gui/guiInventoryList.cpp:217
#2  0x0000555555996229 in GUIInventoryList::OnEvent (this=0x555559275e00, event=...) at /home/tour/Dokumente/yl/minetest/src/gui/guiInventoryList.cpp:182
#3  0x0000555555f4f7f0 in irr::gui::CGUIEnvironment::postEventFromUser (this=0x555557689080, event=...) at /home/tour/Dokumente/yl/minetest/irr/src/CGUIEnvironment.cpp:529
#4  0x0000555555f4be84 in irr::CIrrDeviceStub::postEventFromUser (this=0x5555565b9590, event=...) at /home/tour/Dokumente/yl/minetest/irr/src/CIrrDeviceStub.cpp:205
#5  0x0000555555f3fe92 in irr::CIrrDeviceSDL::run (this=0x5555565b9590) at /home/tour/Dokumente/yl/minetest/irr/src/CIrrDeviceSDL.cpp:790
#6  0x000055555577d5c1 in RenderingEngine::run (this=0x5555565d4ad0) at /home/tour/Dokumente/yl/minetest/src/client/renderingengine.h:141
#7  0x000055555582094c in Game::shutdown (this=0x7fffffffd1f0) at /home/tour/Dokumente/yl/minetest/src/client/game.cpp:1086
#8  0x0000555555834b1b in the_game (kill=0x55555654e360 <porting::g_killed>, input=0x55555768b830, rendering_engine=0x5555565d4ad0, start_data=..., error_message="AsyncErr: Lua: Runtime error from mod 'default' in callback nodemeta_inventory_AllowPut(): .../yl/minetest/games/minetest_game/mods/default/chests.lua:126: attempt to compare number with nil\nstack tra"..., chat_backend=..., reconnect_requested=0x7fffffffd564) at /home/tour/Dokumente/yl/minetest/src/client/game.cpp:4165
#9  0x00005555557af563 in ClientLauncher::run (this=0x7fffffffd920, start_data=..., cmd_args=...) at /home/tour/Dokumente/yl/minetest/src/client/clientlauncher.cpp:203
#10 0x0000555555ca43d2 in main (argc=2, argv=0x7fffffffdde8) at /home/tour/Dokumente/yl/minetest/src/main.cpp:265

Steps to reproduce

• start a server (version does not matter) with a faulty inventory callback (I added a local t = nil > 3 in default:chest's allow_metadata_inventory_put)
• join and perform the inventory action that will lead to the servercrash

Singleplayer segfault too, but it sometimes returns normally to the main menu...