Comment # 6 on bug 1011250 from Neil Brown

The "Code:" line appears to be truncated.  There should be 64 bytes in that
line.
I didn't allow for that properly and so identified the wrong line of code -
slightly.

I now think the crash is happening in:
            list_move(&msg->list, &pipe->in_upcall);
The two pointers in msg->list have been loaded into %rsi and %rcx, and both are
NULL.

I still cannot see how that would happen though.