Lv_obj_clean(lv_scr_act()) causes Segmentation fault

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#1

Description

lv_obj_clean(lv_scr_act()) causes Segmentation fault

What MCU/Processor/Board and compiler are you using?

Linux FB

What do you want to achieve?

Clear screen before each tutorial

What have you tried so far?

Code to reproduce

lv_tutorial_hello_world();
lv_obj_clean(lv_scr_act());
lv_tutorial_objects();

This is inside the while loop inside block if (usCounter++ % 1000 == 0) to change tutorial every 5 seconds.

Screenshot and/or video

If possible, add screenshots and/or videos about the current state.

#2

I’ve just fixed it in the master branch of lvgl.

However note that, lv_tutorial_objects creates and loads a new screen which won’t be deleted by lv_obj_clean. A proper close function would solve it, but tutorials and examples will be reworked in the next release. I’ll take care to do it correctly in the new version.

1 Like
#3

Many thanks, it’s much better. It still seg faults after lv_tutorial_objects() and lv_test_stress_1() as you say.

#4

Hi,

say I have a pointer on the stack to the screen on the heap.

`lv_obj_t* screen;
lv_obj_t* stuff;
lv_scr_load(screen);
stuff = lv_obj_create(screen);
lv_obj_clean(screen);

`
In what case could lv_obj_clean(screen) ever cause a seg fault ? Should lv_obj_clean not iterate through the linked list of allocated objects (children) ? It sometimes causes a seg fault in my app, cause a child is allegedly not there anymore. The only cause I could think of would be a multi-thread sync issue, but I use mutexes before accessing lvgl.
Could there be any other cause than a sync issue ?

Thanks (maybe I should create a new thread, but it is the exact same topic) :slight_smile: