I can reproduce a bug by running a lvm2 snapshot test script on my machine. When it happens, the kernel BUG is triggered and I got the followings in system log: kmem_cache_destroy: Can't free all objects a7f14914 kernel BUG at slab.c:817! invalid operand: 0000 I found out that somehow one of the "dm io" slab cache objects is not released when the snapshot volume is removed. And when dm module is unloaded, the warning message from kmem_cache_destroy shows up. By the time that dm module is reloaded, the kernel BUG is triggered. The kernel is 2.4.26 vanilla + device mapper 2.4.26-rc1 patch + VFS lock patch, the LVMv2 version is 2.00.25, and the file system is XFS. My machine is dell PE2650 (Intel Xeon 2CPUS). The script is like this: #!/bin/sh for i in `seq 1 1000`; do modprobe dm-mod lvchange -a y /dev/myvg/lvol0 mount /dev/myvg/lvol0 /vol1 xfs_freeze -f /vol1 lvcreate -L50G -s -c 512 -n lvmbackup /dev/myvg/lvol0 xfs_freeze -u /vol1 mount /dev/myvg/lvmbackup /mnt/lvmbackup -onouuid,ro,norecovery umount /mnt/lvmbackup lvremove -f /dev/myvg/lvmbackup umount /vol1 lvchange -a n /dev/myvg/lvol0 rmmod dm-mod done Any ideas or suggestions? Thanks. _______________________________ Do you Yahoo!? Declare Yourself - Register online to vote today! http://vote.yahoo.com