On Fri, Jun 21, 2013 at 10:01:48PM +0200, Otto Moerbeek wrote:
> Hi,
>
> I have a Thinkpad T430 with an internal 3G modem that shows up as a
> (couple of) umodem. If I have a connection to the corresponding ucom
> active (with cu or pppd) and suspend the machine followed by a resume,
> it panics (or rather gets a trap) during resume; hand typed:
>
> kernel: protection fault trap, code=0
> Stopped at ehci_check_intr+0xe: movbzl 0x3(%rax),%eax
> dddb{0} trace
> ehci_check_intr at ehci_check_int+0xe
> ehci_softintr() at ehci_softint+0x35
> softintr_dispatch at softintr_dispatch+0x5d
> Xsoftnet() at Xsoftnet+0x2d
>
> rax holds 0xdead0065deadbeef
>
> This is 100% reproducable. If I do not have an active connection to
> cuaU0 at the moment of suspend all is fine and the machine resumes ok.
>
> Could it be the refcounting is still rong in some cases?
>
Likely, but not the same ucom refcounting problem I hit. movbzl
0x3(%rax),%eax is trying to deref bmAttributes, so edesc is freed most
likely. Maybe add some debug printfs to keep track of (de)allocation of
that struct?
