4.8-stable kernel panic

[sysadmin at wvths.com]

> Do you use any klds?  What does kldstat say?
No klds loaded.

Well, it looks like the dc net driver is causing the panic. After some
testing, I got this backtrace:
---
#0  dumpsys () at ../../kern/kern_shutdown.c:487
#1  0xc0168237 in boot (howto=256) at ../../kern/kern_shutdown.c:316
#2  0xc0168675 in panic (fmt=0xc02db260 "m_copydata, offset > size of mbuf
chain") at ../../kern/kern_shutdown.c:595
#3  0xc018576e in m_copydata (m=0xc1560d00, off=6144, len=2048,
cp=0xc155a800 "") at ../../kern/uipc_mbuf.c:979
#4  0xc0186776 in m_defrag (m0=0xc1560d00, how=1) at
../../kern/uipc_mbuf.c:1572
#5  0xc021de70 in dc_encap (sc=0xc21c3000, m_head=0xc1560d00,
txidx=0xd72d9f60) at ../../pci/if_dc.c:3006
#6  0xc021e0bb in dc_start (ifp=0xc21c3000) at ../../pci/if_dc.c:3105
#7  0xc021de09 in dc_intr (arg=0xc21c3000) at ../../pci/if_dc.c:2970
#8  0xc02b419d in intr_mux (arg=0xc144e3a0) at
../../i386/isa/intr_machdep.c:601
#9  0x8068e79 in ?? ()
#10 0x8061e3c in ?? ()
#11 0x8063c75 in ?? ()
#12 0x8061c2a in ?? ()
#13 0x8060047 in ?? ()
#14 0x805ffeb in ?? ()
#15 0x805e3f5 in ?? ()
#16 0x8048e29 in ?? ()
#17 0x804813e in ?? ()
(kgdb) up 3
#3  0xc018576e in m_copydata (m=0xc1560d00, off=6144, len=2048,
cp=0xc155a800 "") at ../../kern/uipc_mbuf.c:979
979                     KASSERT(m != NULL, ("m_copydata, offset > size of
mbuf chain"));
(kgdb) up
#4  0xc0186776 in m_defrag (m0=0xc1560d00, how=1) at
../../kern/uipc_mbuf.c:1572
1572                    m_copydata(m0, progress, length, mtod(m_new,
caddr_t));
(kgdb) up
#5  0xc021de70 in dc_encap (sc=0xc21c3000, m_head=0xc1560d00,
txidx=0xd72d9f60) at ../../pci/if_dc.c:3006
3006                    m = m_defrag(m_head, M_DONTWAIT);
(kgdb) up
#6  0xc021e0bb in dc_start (ifp=0xc21c3000) at ../../pci/if_dc.c:3105
3105                    if (dc_encap(sc, m_head, &idx)) {
(kgdb) up
#7  0xc021de09 in dc_intr (arg=0xc21c3000) at ../../pci/if_dc.c:2970
2970                    dc_start(ifp);
(kgdb) up
#8  0xc02b419d in intr_mux (arg=0xc144e3a0) at
../../i386/isa/intr_machdep.c:601
601                     p->handler(p->argument);
---

After switching to the xl-based NIC, I couldn't reproduce the crash anymore.

Thanks,