Re: kswapd0 oops -> debug information

Randy.Dunlap
2004-11-27T17:05:49Z

Nick Warne wrote:
> Hi all,
>
> I keep getting this oops so randomly, that 'RIGHT, YOU BUGGER' I have
> attempted to supply proper debug info - where I have got is what I learnt
> today, so I am a bit stuck after finding the area of code.

kernel version?
.config file?
full oops message, with stack backtrace?
The stack backtrace could tell us who a bad caller is.
It can just be a caller's problem, not a bug in (this)
one isolated function.

Did you read/check linux/REPORTING-BUGS ?

> ksymoops provides:
>
>
>>>EIP; c0151239 <__iget+29/4c> <=====
>
> Code; c015120e <init_once+1a/1c>
> 00000000 <_EIP>:
> Code; c015120e <init_once+1a/1c>
> 0: 76 00 jbe 2 <_EIP+0x2> c0151210 <__iget+0/4c>
> Code; c0151210 <__iget+0/4c>
> 2: 53 push %ebx
> Code; c0151211 <__iget+1/4c>
> 3: 8b 5c 24 08 mov 0x8(%esp,1),%ebx
> Code; c0151215 <__iget+5/4c>
> 7: 8b 43 1c mov 0x1c(%ebx),%eax
> Code; c0151218 <__iget+8/4c>
> a: 85 c0 test %eax,%eax
> Code; c015121a <__iget+a/4c>
> c: 74 05 je 13 <_EIP+0x13> c0151221
> <__iget+11/4c>
> Code; c015121c <__iget+c/4c>
> e: ff 43 1c incl 0x1c(%ebx)
> Code; c015121f <__iget+f/4c>
> 11: eb 38 jmp 4b <_EIP+0x4b> c0151259
> <__iget+49/4c>
> Code; c0151221 <__iget+11/4c>
>
> 13: ff 43 1c incl 0x1c(%ebx)
> Code; c0151224 <__iget+14/4c>
> 16: f6 83 1c 01 00 00 0f testb $0xf,0x11c(%ebx)
> Code; c015122b <__iget+1b/4c>
> 1d: 75 26 jne 45 <_EIP+0x45> c0151253
> <__iget+43/4c>
> Code; c015122d <__iget+1d/4c>
> 1f: 8d 53 08 lea 0x8(%ebx),%edx
> Code; c0151230 <__iget+20/4c>
> 22: 8b 4a 04 mov 0x4(%edx),%ecx
> Code; c0151233 <__iget+23/4c>
> 25: 8b 43 08 mov 0x8(%ebx),%eax
> Code; c0151236 <__iget+26/4c>
> 28: 89 48 04 mov %ecx,0x4(%eax)
> Code; c0151239 <__iget+29/4c> <=====
> 2b: 89 01 mov %eax,(%ecx) <=====
> Code; c015123b <__iget+2b/4c>
> 2d: a1 6c 9c 30 c0 mov 0xc0309c6c,%eax
> Code; c0151240 <__iget+30/4c>
> 32: 89 50 04 mov %edx,0x4(%eax)
> Code; c0151243 <__iget+33/4c>
> 35: 89 43 08 mov %eax,0x8(%ebx)
> Code; c0151246 <__iget+36/4c>
> 38: c7 42 04 6c 9c 30 c0 movl $0xc0309c6c,0x4(%edx)
> Code; c015124d <__iget+3d/4c>
> 3f: 89 .byte 0x89
>
>
>
> I have traced this code to fs/inode.c. Producing assembler of inode.c gives
> this (snipped):
>
> __iget:
> pushl %ebx
> movl 8(%esp),%ebx
> movl 28(%ebx),%eax
> testl %eax,%eax
> je .L3337
> #APP
> incl 28(%ebx)
> #NO_APP
> jmp .L3336
> .p2align 4,,7
> .L3337:
> #APP
> incl 28(%ebx)
> #NO_APP
> testb $15,284(%ebx)
> jne .L3340
> leal 8(%ebx),%edx
> movl 4(%edx),%ecx
> movl 8(%ebx),%eax
> movl %ecx,4(%eax)
> movl %eax,(%ecx) <===== >>EIP; c0151239 <__iget+29/4c>
> movl inode_in_use,%eax
> movl %edx,4(%eax)
> movl %eax,8(%ebx)
> movl $inode_in_use,4(%edx)
> movl %edx,inode_in_use
> .L3340:
>
>
> Which quiet nicely matches the ksymoops output. My books tell me the inode.s
> file _should_ give me line numbers in inode.c so I can then locate area of
> code - but I can't see how to match the produced assembler to the C source.
>
> Hope this helps someone - and if you know who to get assembler code to match C
> code via line numbers, I would like to know please.
>
> TIA,
>
> Nick

--
~Randy