debug_dma_assert_idle - ohci - cpu touching an active dma mapped cacheline

[poma]

------------[ cut here ]------------
WARNING: CPU: 2 PID: 1065 at lib/dma-debug.c:593 debug_dma_assert_idle+0x159/0x1d0()
ohci-pci 0000:00:04.0: DMA-API: cpu touching an active dma mapped cacheline [cln=0x03004180]
CPU: 2 PID: 1065 Comm: tumblerd Not tainted 3.17.0-0.rc5.git1.1.fc22.i686 #1
Call Trace:
 [<c0b1bdb6>] dump_stack+0x48/0x60
 [<c04591e2>] warn_slowpath_common+0x82/0xa0
 [<c076dad9>] ? debug_dma_assert_idle+0x159/0x1d0
 [<c076dad9>] ? debug_dma_assert_idle+0x159/0x1d0
 [<c045923e>] warn_slowpath_fmt+0x3e/0x60
 [<c076dad9>] debug_dma_assert_idle+0x159/0x1d0
 [<c059a909>] ? anon_vma_prepare+0x29/0x140
 [<c058f594>] do_wp_page+0xe4/0x8c0
 [<c0591792>] handle_mm_fault+0x662/0xba0
 [<c0447398>] __do_page_fault+0x208/0x5d0
 [<c058053b>] ? vm_mmap_pgoff+0x9b/0xc0
 [<c0595178>] ? SyS_mmap_pgoff+0xe8/0x220
 [<c04a8e1c>] ? trace_hardirqs_on_caller+0x13c/0x1e0
 [<c0447760>] ? __do_page_fault+0x5d0/0x5d0
 [<c044777a>] do_page_fault+0x1a/0x20
 [<c0b258b4>] error_code+0x6c/0x74
---[ end trace ce8b30fb8a3415c9 ]---
Mapped at:
 [<c076bb82>] debug_dma_alloc_coherent+0x22/0x70
 [<c09050dc>] ohci_init+0x22c/0x450
 [<c0905359>] ohci_setup+0x59/0x60
 [<c09064cf>] ohci_pci_reset+0x4f/0x60
 [<c08dd8aa>] usb_add_hcd+0x29a/0x8c0

$ lsusb -s 004:
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub


poma