Bug 487894

Description of problem:

After building and installing kernel-2.6.29-0.159.rc6.git3.fc11.src.rpm on a Fedora 10 machine (i7 Core) 

The kernel boots up OK, but displays this error message:

-----------[ cut here ]------------
WARNING: at lib/dma-debug.c:470 check_unmap+0x1cd/0x42e() (Not tainted)
Hardware name: System Product Name
sky2 0000:06:00.0: DMA-API: device driver frees DMA memory with different size [device address=0x0000000033171042] [map size=1520 bytes] [unmap size=0 bytes]
Modules linked in: aoe sky2 e1000e
Pid: 0, comm: swapper Not tainted 2.6.29-0.159.rc6.git3.fc10.i686.PAE #1
Call Trace:
 [<c04383c5>] warn_slowpath+0x7c/0xbd
 [<c04585ae>] ? trace_hardirqs_on_caller+0x10b/0x145
 [<c0448c8b>] ? __kernel_text_address+0x39/0x43
 [<c040c067>] ? print_context_stack+0x8d/0x9e
 [<c0458079>] ? mark_lock+0x1e/0x349
 [<c04572f9>] ? register_lock_class+0x17/0x290
 [<c0558db9>] ? check_unmap+0x65/0x42e
 [<c0558f21>] check_unmap+0x1cd/0x42e
 [<c0552653>] ? random32+0x16/0x18
 [<c05584c5>] ? should_fail+0x80/0x14b
 [<c040df5b>] ? sched_clock+0x8/0xb
 [<c040df5b>] ? sched_clock+0x8/0xb
 [<c04adeb0>] ? check_valid_pointer+0x24/0x53
 [<c04ae51d>] ? check_object+0x131/0x165
 [<c0559358>] debug_dma_unmap_page+0x59/0x61
 [<f80a25f9>] dma_unmap_single+0x4c/0x57 [sky2]
 [<f80a263f>] sky2_rx_unmap_skb+0x3b/0xa5 [sky2]
 [<f80a2052>] ? sky2_rx_alloc+0x61/0xdb [sky2]
 [<f80a4e77>] sky2_poll+0x569/0x97a [sky2]
 [<c06852a4>] ? net_rx_action+0x189/0x1ca
 [<c06851bc>] net_rx_action+0xa1/0x1ca
 [<c043d276>] __do_softirq+0x9d/0x157
 [<c043d1d9>] ? __do_softirq+0x0/0x157
 <IRQ>  [<c047b642>] ? handle_edge_irq+0x0/0xf2
 [<c043cf1a>] ? irq_exit+0x49/0x77
 [<c040b2b3>] ? do_IRQ+0xf5/0x10b
 [<c0409dac>] ? common_interrupt+0x2c/0x34
 [<c045007b>] ? __async_schedule+0x90/0x120
 [<c040ee11>] ? mwait_idle+0x77/0xa7
 [<c0408798>] ? cpu_idle+0x70/0x90
 [<c07093a5>] ? start_secondary+0x1c9/0x1d1
---[ end trace bf70a1302e043c63 ]---

Version-Release number of selected component (if applicable):
2.6.29-0.159.rc6.git3.fc10.i686.PAE

How reproducible:

I boot the kernel via PXE, I've modified the initrd so load the Sky ethernet driver so that I can boot from an AOE server.

I've added the following to the init script (so I can boot via AOE)

echo "Loading sky2  module"
modprobe -q sky2
sleep 2
#==============================
busybox ifconfig eth0 up
busybox ifconfig eth1 up
sleep 4
echo "Creatig AOE /dev entries"
mknod /dev/etherd/stat       c 152 1
mknod /dev/etherd/err        c 152 2
mknod /dev/etherd/discover   c 152 3
mknod /dev/etherd/interfaces c 152 4
mknod /dev/etherd/revalidate c 152 5
mknod /dev/etherd/flush      c 152 6
echo "Loading aoe module"
modprobe -q aoe aoe_iflist="eth0,eth1"
echo "Scanning AOE network for disks"
echo "1" > /dev/etherd/discover
sleep 1
mkblkdevs
#=============================

Steps to Reproduce:
1. boot via PXE with modified initrd
2.
3.
  
Actual results:

sky2 0000:06:00.0: DMA-API: device driver frees DMA memory with different size [device address=0x0000000033171042] [map size=1520 bytes] [unmap size=0 bytes]

Expected results:

No message should appear.

I would imagine that the above unmap should release 1520 bytes rather than 0 bytes.

Additional info:

The above works fine with all previous kernels, so I would expect it to work with the newer .28/.29 kernels too.