dma warning in hardy kernel

I see this repeatedly in syslog

[ 4074.960149] WARNING: at /build/buildd/linux-2.6.24/arch/x86/kernel/pci-dma_64.c:169 dma_free_coherent()
[ 4074.960152] Pid: 19831, comm: cli64 Not tainted 2.6.24-8-server #1
[ 4074.960153]
[ 4074.960154] Call Trace:
[ 4074.960157] [<ffffffff802144ca>] dma_alloc_coherent+0x13a/0x200
[ 4074.960161] [<ffffffff80214283>] dma_free_coherent+0xa3/0xb0
[ 4074.960166] [<ffffffff880f8540>] :arcmsr:arcmsr_queue_command+0x890/0x9a0
[ 4074.960177] [<ffffffff880c800c>] :scsi_mod:scsi_dispatch_cmd+0x17c/0x2e0
[ 4074.960187] [<ffffffff880ced75>] :scsi_mod:scsi_request_fn+0x225/0x3d0
[ 4074.960191] [<ffffffff8033bf72>] blk_execute_rq_nowait+0x62/0xb0
[ 4074.960200] [<ffffffff880ce644>] :scsi_mod:scsi_execute_async+0x1f4/0x3e0
[ 4074.960208] [<ffffffff881d34df>] :sg:sg_common_write+0x18f/0x930
[ 4074.960212] [<ffffffff881d3f50>] :sg:sg_cmd_done+0x0/0x2c0
[ 4074.960216] [<ffffffff80468070>] thread_return+0x3a/0x59a
[ 4074.960222] [<ffffffff881d3e4d>] :sg:sg_new_write+0x1cd/0x2d0
[ 4074.960227] [<ffffffff881d5c65>] :sg:sg_ioctl+0x4c5/0xb60
[ 4074.960230] [<ffffffff80468d59>] do_nanosleep+0x69/0x90
[ 4074.960233] [<ffffffff80257538>] hrtimer_nanosleep+0x78/0x140
[ 4074.960236] [<ffffffff802bd16d>] do_ioctl+0x7d/0xa0
[ 4074.960240] [<ffffffff802bd3b0>] vfs_ioctl+0x220/0x2c0
[ 4074.960244] [<ffffffff802bd4e1>] sys_ioctl+0x91/0xb0
[ 4074.960247] [<ffffffff8020c37e>] system_call+0x7e/0x83

# cat /proc/version
Linux version 2.6.24-8-server (buildd@yellow) (gcc version 4.2.3 (Ubuntu 4.2.3-1ubuntu2)) #1 SMP Thu Feb 14 20:42:20 UTC 2008

This is a hardy kernel on gutsy
# cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=7.10
DISTRIB_CODENAME=gutsy
DISTRIB_DESCRIPTION="Ubuntu 7.10"

There's an Areca 1230 SATA controller in the system. To trigger the warning, I can run the Areca command line utility "cli64" which is some presumably closed source RAID management tool. Or at least it was a binary download. Running it and asking what disks are attached to the controller "rsf info" triggers the warning.

I have no idea if this warning matters in the slightest, but thought it best to report.