CURRENT: re(4) crashing system

I tried to report earlier here that CURRENT does have some serious
problems right now and one of those problems seems to be triggered by
the recent re(4) driver. The problem is also present in recen 11-STABLE!

Below, you'll find pciconf-output reagrding the device on a Lenovo E540
Laptop I can test on and trigger the problem.

The phenomenon is that this NIC does not negotiate 1000baseTX, it is
always falling back to 100baseTX although the device claims to be a 1
GBit capable device.

When I try to put the device manually into 1000basTX mode via

ifconfig re0 media 1000baseTX mediaopt full-duplex (with re(4) driver)

it is possible to crash the system. The system also crashes when
plugging/unplugging the LAN cord - I guess the renegotiation is
triggering this crash immediately.

I tried with several switches and routers capable of 1 GBit and it
seems to be independent from the network hardware in use.

I tried to capture a backtrace when the kernel crashes, but I do not
know how to save the the kernel debugger output. Although I configured
according the handbook debugging, there is no coredump at all.

Advice is appreciated - if anybody is interesetd in solving this. 

Thank you very much in advance and kind regards,

Oliver

[...]
re0_at_pci0:3:0:0: class=0x020000 card=0x502817aa chip=0x816810ec rev=0x10
hdr=0x00 vendor     = 'Realtek Semiconductor Co., Ltd.'
    device     = 'RTL8111/8168/8411 PCI Express Gigabit Ethernet
Controller' class      = network
    subclass   = ethernet
    bar   [10] = type I/O Port, range 32, base 0x3000, size 256, enabled
    bar   [18] = type Memory, range 64, base 0xf0d04000, size 4096,
enabled bar   [20] = type Memory, range 64, base 0xf0d00000, size
16384, enabled cap 01[40] = powerspec 3  supports D0 D1 D2 D3  current
D0 cap 05[50] = MSI supports 1 message, 64 bit 
    cap 10[70] = PCI-Express 2 endpoint MSI 1 max data 128(128) RO
                 link x1(x1) speed 2.5(2.5) ASPM disabled(L0s/L1)
    cap 11[b0] = MSI-X supports 4 messages, enabled
                 Table in map 0x20[0x0], PBA in map 0x20[0x800]
    cap 03[d0] = VPD
    ecap 0001[100] = AER 2 0 fatal 0 non-fatal 0 corrected
    ecap 0002[140] = VC 1 max VC0
    ecap 0003[160] = Serial 1 01000000684ce000
    ecap 0018[170] = LTR 1
    ecap 001e[178] = unknown 1