STREAMS/UX for the HP 9000 Reference Manual

170
Debugging STREAMS/UX Modules and Drivers
HP-UX Kernel Debugging Tools and strdb
trap type 6 pcsq.pcoq = 0.0 isr.ior = 4.78
@(#)9245XA HP-UX (A.10.00) #0: Sat Aug 13 23:17:54 PDT 1994
panic: (display==0xbf00, flags==0x0) Instruction page fault
The pcsq.pcoq pair is important; the user attempted to jump to page zero and
start executing. In this case, because the fault was an instruction page fault,
the isr.ior pair is meaningless. The page fault may have occurred because of
an indirect procedure call, where the address of the routine to be called was
not initialized.
Protection Violations
A third common panic is the protection violation. This type of panic occurs
when the kernel tries to reference a data structure that does not belong to the
current process. This panic also occurs if the kernel attempts to reference an
object in a way which is not permitted by the access rights assigned to the
page where the object resides, for example, an attempt to write on a
read-only page. Another frequently overlooked area of protection faults are
unaligned access violations. These appear to be protection faults, but are
caused by performing an operation on an unaligned address, for example,
load word on a non-word aligned address. In each of these cases, trap type
18 or 7 would be generated. The pcsq.pcoq pair would give the offending
instruction, and the isr.ior would give the offending data address referenced.