UML mode panick under 2.6.12

UML mode panick under 2.6.12

[XIAO Gang]

I am unable to run UML mode (i386) under 2.6.12: the execution gives the 
following messages.

---------------------------------------------------------------------------------------------
Checking for /proc/mm...not found
Checking PROT_EXEC mmap in /tmp...OK
tracing thread pid = 26236
<5>Linux version 2.6.12 (xiao@cim06-1-82-234-179-206.fbx.proxad.net) 
(gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)) #22 Tue Jun 21 
09:21:30 CEST 2005
<7>On node 0 totalpages: 8192
<7>  DMA zone: 8192 pages, LIFO batch:3
<7>  Normal zone: 0 pages, LIFO batch:1
<7>  HighMem zone: 0 pages, LIFO batch:1
Built 1 zonelists
<5>Kernel command line: root=98:0
PID hash table entries: 256 (order: 8, 4096 bytes)
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
<6>Memory: 29500k available
<7>Calibrating delay loop... 1802.24 BogoMIPS (lpj=9011200)
Mount-cache hash table entries: 512
Checking for host processor cmov support...Yes
Checking for host processor xmm support...No
Checking that ptrace can change system call numbers...<0>Kernel panic - 
not syncing: Segfault with no mm

EIP: 0023:[<00000000>] CPU: 0 Not tainted ESP: 002b:a01a7f58 EFLAGS: 
00010207
    Not tainted
EAX: 00000000 EBX: a01a7f60 ECX: 00000000 EDX: a01d4a00
ESI: 00000000 EDI: 00000000 EBP: 00000002 DS: 002b ES: 002b
a01a7a38:  [<a002db01>] show_regs+0x1dd/0x1e8
a01a7a68:  [<a0018e37>] panic_exit+0x27/0x48
a01a7a88:  [<a004215e>] notifier_call_chain+0x22/0x40
a01a7ab8:  [<a0031a66>] panic+0x56/0x104
a01a7ad8:  [<a00182ee>] segv+0x1be/0x254
a01a7bb8:  [<a00186a8>] segv_handler+0x11c/0x180
a01a7bf8:  [<a001b7fd>] sig_handler_common_tt+0xa9/0x124
a01a7c58:  [<a002965f>] sig_handler+0x1f/0x34
a01a7c78:  [<a012b4e8>] __restore+0x0/0x8

---------------------------------------------------------------------------------------------

By the way, the output beyond the first three lines has to be printed 
out after a hack of printk(), as the latter usually failed to print out 
anything.

The kernel is compiled with a ported config from 2.6.10-um, and is run 
under exactly the same condition as the 2.6.10 counterpart which works 
fine. The host is under Linux-2.4.31.

-- 

XIAO Gang (~{P$8U~})                          xiao@unice.fr
          home page: pcmath126.unice.fr/xiao.html 

Re: UML mode panick under 2.6.12

[Jeff Dike]

On Tue, Jun 21, 2005 at 09:25:46AM +0200, XIAO Gang wrote:
> 
> I am unable to run UML mode (i386) under 2.6.12: the execution gives the 
> following messages.
> 
> ---------------------------------------------------------------------------------------------

> Checking that ptrace can change system call numbers...<0>Kernel panic - 
> not syncing: Segfault with no mm

Can you try backing out the use-fork-instead-of-clone patch?  Ben LaHaise
reported that caused problems for him.

				Jeff

Re: UML mode panick under 2.6.12

[XIAO Gang]

Jeff Dike wrote:

>On Tue, Jun 21, 2005 at 09:25:46AM +0200, XIAO Gang wrote:
>  
>
>>I am unable to run UML mode (i386) under 2.6.12: the execution gives the 
>>following messages.
>>
>>---------------------------------------------------------------------------------------------
>>    
>>
>
>  
>
>>Checking that ptrace can change system call numbers...<0>Kernel panic - 
>>not syncing: Segfault with no mm
>>    
>>
>
>Can you try backing out the use-fork-instead-of-clone patch?  Ben LaHaise
>reported that caused problems for him.
>  
>
Not wanting to bother trimming things out, I have just copied 
arch/um/kernel/process.c from that in 2.6.10 then recompile. And 
everything works fine. So the problem is there, but I don't know how 
exactly.

-- 

XIAO Gang (~{P$8U~})                          xiao@unice.fr
          home page: pcmath126.unice.fr/xiao.html