Linux 2.6.24 L4FB and VGA_CONSOLE

[Adam Lackorzynski]

Salut Marc,

On Wed Feb 20, 2008 at 19:01:25 +0100, Marc CHALAND wrote:
> I made a svn up into l4linux-2.6, made an oldconfig and encountered
> some problems with lxevent and... cron (???). Problem with lxevent,
> was into rmgr_init_ping_call: _dice_msg_buffer was NULL.
> 
> So I decided to purge all build directories (fiasco, build dir,
> install dir and l4linux). I edited a new configuration for l4linux but
> I encountered a problem : I cannot disable VGA_CONSOLE if I don't use
> EMBEDDED.

Yes, that's Linux trying to prevent you from doing stupid things :)

> So I decided to set it. But, now, I've got some stability
> problems : I get the following message :
 
I think it has nothing to do with CONFIG_EMBEDDED.

> ---------------------------------------------------------------------------------------------------------------------------------
> KERNEL: set_tls: non-existing thread 003401e1
> 
> KERNEL: set_ldt: non-existing task 0.
> Trap: 13: 0000 [#1]
> Modules linked in:
> 
> Pid: 1070, comm: consolechars Not tainted (2.6.24-l4 #14)
> EIP: ff7c:[<00405055>] EFLAGS: 00010246 CPU: 0
> EIP is at l4x_switch_to+0xd0/0xd3
> EAX: 1003cc60 EBX: 00000018 ECX: 00000000 EDX: 00000000
> ESI: 003401e1 EDI: 1003ca80 EBP: 1081013c ESP: 108139a0
>  DS: 0000 ES: 4280 FS: 0023 GS: 0043 SS: 0023
> Process consolechars (pid: 1070, ti=10812000 task=1003ca80 task.ti=108d0000)
> Stack: 108139a8 00000000 1003ca80 10810000 00000400 0054da88 005f0fbc 10810000
>        00000400 1003ca80 10812000 108139e8 ffff950d 00000400 0000000b 0054dd5b
>        108139e8 ffff950d 005f67b0 005f67b0 ffff950d 0041923c 10810000 005f5f00
> Call Trace:
>  [<0054da88>] schedule+0x171/0x1bb
>  [<0054dd5b>] schedule_timeout+0x7b/0x99
>  [<0041923c>] process_timeout+0x0/0x9
>  [<0045672f>] do_select+0x397/0x3ee
>  [<00456d5f>] __pollwait+0x0/0xaf
>  [<0040eeff>] default_wake_function+0x0/0x14
>  [<0049f877>] __make_request+0x472/0x4a8
>  [<0040e891>] update_curr+0x52/0xc8
>  [<0040eb9b>] dequeue_entity+0xb/0x2a
>  [<0040fbbf>] dequeue_task_fair+0x1b/0x2f
>  [<0040f644>] finish_task_switch+0x1f/0x50
>  [<0054dab4>] schedule+0x19d/0x1bb
>  [<0054dcca>] io_schedule+0xb/0x12
>  [<00467424>] sync_buffer+0x3b/0x40
>  [<0054debd>] __wait_on_bit+0x53/0x5c
>  [<004673e9>] sync_buffer+0x0/0x40
>  [<004673e9>] sync_buffer+0x0/0x40
>  [<0054df28>] out_of_line_wait_on_bit+0x62/0x6a
>  [<00421d9c>] wake_bit_function+0x0/0x34
>  [<004820b3>] __ext3_get_inode_loc+0x29e/0x2f6
>  [<00448a95>] kmem_cache_alloc+0x66/0x9e
>  [<0045a1da>] __d_lookup+0x97/0xd5
>  [<0045a1da>] __d_lookup+0x97/0xd5
>  [<00451dd2>] do_lookup+0x59/0x16b
>  [<00453837>] __link_path_walk+0x930/0xa72
>  [<0045a6a3>] dput+0x2a/0xe5
>  [<00453837>] __link_path_walk+0x930/0xa72
>  [<0045d5ea>] mntput_no_expire+0x1c/0x5c
>  [<0045697e>] core_sys_select+0x1f8/0x2ae
>  [<00454514>] __user_walk_fd+0x43/0x4c
>  [<00449151>] kmem_cache_free+0x40/0x93
>  [<00452d6f>] getname+0x68/0xa2
>  [<0044e26d>] cp_new_stat64+0xff/0x111
>  [<00456eb3>] sys_select+0xa5/0x173
>  [<0040401b>] l4x_user_dispatcher+0x8e2/0x184c
>  [<0040c030>] _upage_start+0x30/0x890
>  [<00456e0e>] sys_select+0x0/0x173
>  [<0044fd40>] do_execve+0x172/0x17b
>  [<0044fd40>] do_execve+0x172/0x17b
>  [<005c4372>] kernel_init+0x0/0x254
>  [<004079a3>] l4_kernelinternal_execve+0xc2/0xc9
>  [<00400915>] in_kernel_int80_helper+0x9/0x17
>  [<005c4372>] kernel_init+0x0/0x254
>  [<004094a3>] kernel_execve+0x17/0x1a
>  [<00400198>] run_init_process+0x20/0x24
>  [<00400242>] init_post+0xa6/0xd0
>  [<005c45bc>] kernel_init+0x24a/0x254
>  [<0040f644>] finish_task_switch+0x1f/0x50
>  [<005c4372>] kernel_init+0x0/0x254
>  [<005c4372>] kernel_init+0x0/0x254
>  [<004072cb>] kernel_thread_start+0x28/0x2d
>  [<00406ed2>] sys_enosys+0x0/0x6
>  =======================
> Code: 00 00 89 04 d5 04 e0 5a 00 89 0c d5 00 e0 5a 00 8b b7 00 02 00 00 8d 87 e0
>  01 00 00 bb 18 00 00 00 31 c9 89 ca 0f 00 d0 5b 5e 5f <c3> 90 90 57 56 83 ec 04
>  8b 74 24 10 8b 7c 24 14 f6 46 0d 20 74
> EIP: [<00405055>] l4x_switch_to+0xd0/0xd3 SS:ESP 0023:108139a0
> ---[ end trace 10d172b22dcd8354 ]---
> Fixing recursive fault but reboot is needed!
> ------------------------------------------------------------------------------------------------------------------------
> 
> I thought I forgot to set an option into kernel. But this happens
> sometimes on egrep, which, etc..
> Any idea on the problem ?

The fault is on the ret of l4x_switch_to which somehow looks like  a
corrupt stack. Also there are errors from the load_TLS call which is
also strange. With 'sometimes', do you mean it's hard to trigger or
rather that it doesn't matter which program you use? Just for
completeness, did you upgrade your Linux distribution you're running
inside L4Linux? Or any other change?
If you comment in the LOG_printf in l4x_switch_to
(arch/l4/kernel/arch-i386/dispatch.c), do it work ok or is there
something strange (e.g. sane PIDs, etc.)?



Adam
-- 
Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/