Re: [linux-lvm] (no subject)

From: Heinz Mauelshagen <mauelshagen@redhat.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Cc: hjm@redhat.com
Subject: Re: [linux-lvm] (no subject)
Date: Sun, 20 Jun 2004 10:46:16 +0200	[thread overview]
Message-ID: <20040620084616.GA3519@redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0406181723320.4709@pc167.cc.le.ac.uk>

Alex,

could you run that through ksymoops to get a backtrace ?

Regards,
Heinz    -- The LVM Guy --

On Fri, Jun 18, 2004 at 05:33:00PM +0100, Alex Owen wrote:
> Hello,
> This morning I had an oops which I think is due to extending a
> LVM1 LVsnapshot.
> 
> I'm running a custom compiled 2.4.26 kernel. Debian source + LVM1.0.8 +
> VFS-Lock from dm tarball.
> 
> If anyone can give me any pointers to informantion of debuging such
> problems that would be great!
> 
> Thanks in advance for any advice on debugging.
> 
> 
> Here is the syslog output:
> Jun 18 07:39:02 falcon /USR/SBIN/CRON[3094]: (root) CMD ([ -x /usr/local/sbin/cron.snapshotextend ] && /usr/local/sbin/cron.snapshotextend)
> Jun 18 07:39:03 falcon kernel: Unable to handle kernel NULL pointer dereference at virtual address 00000000
> Jun 18 07:39:03 falcon kernel:  printing eip:
> Jun 18 07:39:03 falcon kernel: f8855b17
> Jun 18 07:39:03 falcon kernel: *pde = 1236b001
> Jun 18 07:39:03 falcon kernel: *pte = 00000000
> Jun 18 07:39:03 falcon kernel: Oops: 0000
> Jun 18 07:39:03 falcon kernel: CPU:    3
> Jun 18 07:39:03 falcon kernel: EIP:    0010:[ide-cd:__insmod_ide-cd_O/lib/modules/2.4.26-686-smp-lvm-vfslock/ke+-2135273/96]    Tainted: P
> Jun 18 07:39:03 falcon kernel: EFLAGS: 00010202
> Jun 18 07:39:03 falcon kernel: eax: 00000000   ebx: f8ac3260   ecx: 00000000   edx: 00000000
> Jun 18 07:39:03 falcon kernel: esi: 00402400   edi: f724aa00   ebp: 00006804   esp: c43d7dd0
> Jun 18 07:39:03 falcon kernel: ds: 0018   es: 0018   ss: 0018
> Jun 18 07:39:03 falcon kernel: Process kupdated (pid: 9, stackpage=c43d7000)
> Jun 18 07:39:03 falcon kernel: Stack: f724aa00 f724ab70 f7c92970 00200000 00000080 00000002 00000000 00000000
> Jun 18 07:39:03 falcon kernel:        f88526d1 c43d7e2e c43d7e30 00402380 f724aa00 00003a02 eda084a0 00000080
> Jun 18 07:39:03 falcon kernel:        00200000 c7d80f80 000c00b0 f7c92800 f7c89000 00402380 00000000 68040000
> Jun 18 07:39:03 falcon kernel: Call Trace:    [ide-cd:__insmod_ide-cd_O/lib/modules/2.4.26-686-smp-lvm-vfslock/ke+-2148655/96]
> [ide-cd:__insmod_ide-cd_O/lib/modules/2.4.26-686-smp-lvm-vfslock/ke+-2148425/96] [generic_make_request+288/304] [submit_bh+86/224]
> [write_locked_buffers+32/44]
> Jun 18 07:39:03 falcon kernel:   [write_some_buffers+278/364] [sync_old_buffers+101/168] [kupdate+329/384] [ret_from_fork+6/32] [kupdate+0/384]
> [arch_kernel_thread+40/56]
> Jun 18 07:39:03 falcon kernel:
> Jun 18 07:39:03 falcon kernel: Code: 8b 01 39 d9 74 37 39 71 08 75 ef 66 39 69 0c 75 e9 83 7c 24
> 
> The cron job I suspect of trigering the kernel bug is
> /usr/local/sbin/cron.snapshotextend :
> 
> ---8<---
> #!/bin/bash
> #################################################
> # script to extend snapshots before they fill up!
> #################################################
> 
> 
> #for lv in /dev/vg00/SNAP* ; do
> for lv in $( ls /dev/vg00/SNAP* 2>/dev/null )  ; do
>     /sbin/lvdisplay $lv | grep "Allocated to snapshot" | \
> 	( read junk junk junk LVpercent LVvalues
> 	  #make integer percentage
> 	  LVpercent=${LVpercent%\%}
> 	  LVpercent=${LVpercent%.*}
> 	  #get usage and size from values
> 	  LVusage=${LVvalues%%/*]}
> 	  LVusage=${LVusage#[}
> 	  LVsize=${LVvalues##[*/}
> 	  LVsize=${LVsize%]}
> 
> 	  #echo lv $lv
> 	  #echo percent $LVpercent
> 	  #echo used $LVusage
> 	  #echo size $LVsize
> 
> 	  if /usr/bin/expr $LVpercent '>=' 80  >/dev/null ; then
> 
> 		LVsizeunit=${LVsize##* }
> 		LVsizeunit=${LVsizeunit%B}
> 		#calc 20% of existing snapshot size
> 		LVextension=${LVsize%% *}
> 		LVextension=${LVextension%.*}
> 		LVextension=$(( $LVextension * 20 / 100 ))
> 
> 		echo /sbin/lvextend -L+$LVextension$LVsizeunit $lv
> 		/sbin/lvextend -L+${LVextension}${LVsizeunit} $lv
> 		echo DONE
> 	  fi
> 
> 	)
> 
> done
> ---8<---
> 
> 
> 
> 
> ----------------------------------------------------------------
>  Dr Richard Alexander Owen      Unix System Administrator
> 
>  The Computer Centre            E-mail: rao3@le.ac.uk
>  University of Leicester           Tel: (0116) 2525133
>  University Road                   Fax: (0116) 2525027
>  Leicester LE1 7RH
> ----------------------------------------------------------------
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*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

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Heinz Mauelshagen                                 Red Hat GmbH
Consulting Development Engineer                   Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen@RedHat.com                            +49 2626 141200
                                                       FAX 924446
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