Task switch problem...

[Ozguxxx]

Hi people, when I try to do a very simple task switch in bochs, it gives an error like:

...
00000330071i[KBD ] reset-disable command received
00000506022e[HD ] device set to 0 which does not exist
00000506315e[HD ] device set to 1 which does not exist
00000713774i[CPU ] task_switch: bad LDT fetch
00000713774i[CPU ] task switch: posting exception 10 after commit point
00000713774p[CPU ] >>PANIC<< can_push(): SS invalidated.
00000713774i[SYS ] Last time is 1044651487
00000713774i[CPU ] protected mode
00000713774i[CPU ] CS.d_b = 32 bit
00000713774i[CPU ] SS.d_b = 32 bit
00000713774i[CPU ] | EAX=000000ec EBX=00000100 ECX=00163c00 EDX=00000100
00000713774i[CPU ] | ESP=0000ffff EBP=00000000 ESI=0000395f EDI=00000005
00000713774i[CPU ] | IOPL=0 NV UP DI PL NZ NA PE NC
00000713774i[CPU ] | SEG selector base limit G D
00000713774i[CPU ] | SEG sltr(index|ti|rpl) base limit G D
00000713774i[CPU ] | DS:0010( 0002| 0| 0) 00001000 000fffff 1 1
00000713774i[CPU ] | ES:0010( 0002| 0| 0) 00001000 000fffff 1 1
00000713774i[CPU ] | FS:0010( 0002| 0| 0) 00001000 000fffff 1 1
00000713774i[CPU ] | GS:0008( 0001| 0| 0) 00001000 000fffff 1 1
00000713774i[CPU ] | SS:0010( 0002| 0| 0) 00001000 000fffff 1 1
00000713774i[CPU ] | CS:0018( 0003| 0| 0) 00001000 000fffff 1 1
00000713774i[CPU ] | EIP=000000e7 (000000e7)
00000713774i[CPU ] | CR0=0x60000019 CR1=0x00000000 CR2=0x00000000
00000713774i[CPU ] | CR3=0x00000000 CR4=0x00000000
00000713774i[ ] restoring default signal behavior
00000713774i[CTRL ] quit_sim called with exit code 1


Any ideas? Thanx...

[Therx]

It's hard to tell without seeing your exact code but

00000713774p[CPU ] >>PANIC<< can_push(): SS invalidated.

suggests that you aren't updating the stack registers after a switch. Each task needs it's own stack and you must restore ALL registers to the state they were in when you left the task.