kern/121770: ZFS on i386, large file or heavy I/O leads to kernel panic or reboot

[Solra Bizna]

>Number:         121770
>Category:       kern
>Synopsis:       ZFS on i386, large file or heavy I/O leads to kernel panic or reboot
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Mar 17 00:00:03 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     Solra Bizna
>Release:        7.0-RELEASE
>Organization:
>Environment:
FreeBSD geordi 7.0-RELEASE FreeBSD 7.0-RELEASE #0: Sun Feb 24 19:59:52 UTC 2008     root at logan.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386

>Description:
I have a SPARC64 with 1.25GB of RAM running 7.0-RC1, and I'm migrating a filesystem from it to an i386 with 1.5GB of RAM running 7.0-RELEASE. One of the filesystems was around 3GB in size. I used zfs send to create snapshot files of each filesystem, and transferred them over to a temporary ZFS filesystem using rsync. Sometimes at random (but consistently partway through the 3GB file) the i386 panics with a "page fault in kernel mode" and an access to a very low (always 0x1 when I was at the console to see it) address.
Just now, the temporary filesystem in question was corrupted, leading ZFS to freeze. This is (IMO) probably just the same error manifesting itself in a different way. The problem also manifests itself as a sudden, inexplicable reboot.
I had not followed the instructions in ZFSTuningGuide, but the problem is still reproducible after having done so.
>How-To-Repeat:
$ dd if=/dev/zero of=/somepool/test bs=2048 count=1048576
Were it to work, it would create a 2GB file filled with zeroes. Sometimes a 1GB file is enough to trigger this.

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: