When your OS goes crazy - Screenshots

[Muazzam]

Are you sure it's a bug, nicknytko?

[Roman]

Are you sure it's a bug, nicknytko?

"It's not a bug. It's a feature!"

[Muazzam]

Are you sure it's a bug, nicknytko?

"It's not a bug. It's a feature!"

haha.

But I was serious.

[nicknytko]

Are you sure it's a bug, nicknytko?

"It's not a bug. It's a feature!"

haha.

But I was serious.

hahaha yes, it was an accident
my printDecimal had a bug where if the input number was zero, it would infinite loop and overwrite the first 48kb of memory

[mallard]

Working on my "Terminal Emulator" recently. While trying some optimisations to speed up the display (it's way too slow at the moment), I got this:



It has something to do with telling the graphics subsystem to update zero-sized areas of the screen, but I only got this after I added a check for that... Also, I have no idea why the text is purple.

[cmpxchg64]

There are still some syncing issues present. Some old code is still not fully preeption-aware and explodes if "real preemption", that is preemption plus concurrency kicks in.

The culprit lies in the design of one of my printf-functions which has a "internal_vprintf" that works on a ivp_ctx structure with a putchar-callback (one for string, one for framebuffers, ...). The structure on the stack gets damaged as sometime miracously two processors work on the same stack, which is a bit surprising as the "scheduler's log" clearly shows, that each task uses it's own stack. Additionally each task has a running flag, disallowing the usage of the stack for other task_schedule calls.

The scheduler is an implementation of the rotating staircase scheduler, kredraw is in the queue with highest priority, which explains the 10 context switches towards it.
(kredraw -> task_yield -> kredraw -> task_yield -> until quota=0 and cur_prio--)

[bellezzasolo]

I was experimenting with SMP in my OS. I have the cores in 32 bit mode, so was now trying to start them up. Of course, I had to go and trigger a fault... on BOTH cores.

[osdever]

When I'm tested TTY scrolling. Looks like it's not working well

[Enerccio]

When you have bug in your scroll routine:

[cheapskate01]

Me, trying to fill my Vesa Framebuffer with a Material design Color:



and a few seconds later:

qemu: fatal: Trying to execute code outside RAM or ROM at 0x8210043b

EAX=04106003 EBX=0015ac09 ECX=000000ff EDX=03380000
ESI=00000001 EDI=00ffe082 EBP=00000000 ESP=00106004
EIP=8210043b EFL=00000007 [-----PC] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0018 00000000 ffffffff 00cf9300 DPL=0 DS [-WA]
CS =0010 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0018 00000000 ffffffff 00cf9300 DPL=0 DS [-WA]
DS =0018 00000000 ffffffff 00cf9300 DPL=0 DS [-WA]
FS =0018 00000000 ffffffff 00cf9300 DPL=0 DS [-WA]
GS =0018 00000000 ffffffff 00cf9300 DPL=0 DS [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT= 00108240 00000020
IDT= 00000000 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000
DR6=ffff0ff0 DR7=00000400
CCS=000001ff CCD=000000ff CCO=SARL
EFER=0000000000000000
FCW=037f FSW=0000 [ST=0] FTW=00 MXCSR=00001f80
FPR0=0000000000000000 0000 FPR1=0000000000000000 0000
FPR2=0000000000000000 0000 FPR3=0000000000000000 0000
FPR4=0000000000000000 0000 FPR5=0000000000000000 0000
FPR6=0000000000000000 0000 FPR7=0000000000000000 0000
XMM00=00000000000000000000000000000000 XMM01=00000000000000000000000000000000
XMM02=00000000000000000000000000000000 XMM03=00000000000000000000000000000000
XMM04=00000000000000000000000000000000 XMM05=00000000000000000000000000000000
XMM06=00000000000000000000000000000000 XMM07=00000000000000000000000000000000
Aborted (core dumped)

[cheapskate01]

LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
GDT= 00108240 00000020
IDT= 00000000 00000000

Does that mean I did Gdt and Idt successfully?

[Roman]

LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
GDT= 00108240 00000020
IDT= 00000000 00000000

Does that mean I did Gdt and Idt successfully?

I don't think so.

[cheapskate01]

LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
GDT= 00108240 00000020
IDT= 00000000 00000000

Does that mean I did Gdt and Idt successfully?

I don't think so.

Brainfart. I didn't build Gdt and Idt in this code fork Lol

[cmpxchg64]

That's the result of transfering 5 2/3rds 24-bit pixels via the SSE movdqa into the framebuffer. The 24-bit pixel format is the most tricky one to get right, innit?

[cheapskate01]

My failure to add a clear screen function :/
I have no Idea how to fix it. No matter what I do, the background is green.