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(dbx) px savedefp[28]
8
0xfffffc000032972c
(dbx) savedefp[28]/i
9
[nfs_putpage:2344, 0xfffffc000032972c] ldl r5, 40(r1)
(dbx) savedefp[23]/i
10
[ubc_invalidate:1768, 0xfffffc0000315fe0] stl r0, 84(sp)
(dbx) func nfs_putpage
11
(dbx) file 12
/usr/sde/alpha/build/alpha.nightly/src/kernel/kern/sched_prim.c
(dbx) func ubc_invalidate
13
ubc_invalidate: Source not available
(dbx) file
14
/usr/sde/alpha/build/alpha.nightly/src/kernel/vfs/vfs_ubc.c
(dbx) q
1 You can use the sh command to enter commands to the shell. In this
case, enter the stings and grep commands to pull the operating
system revision number in the vmunix.1 dump file.
2 Display the utsname structure to obtain more information about the
operating system version.
3 Display the panic string (panicstr). The panic function was called
by a trap function.
4 Perform a stack trace. This confirms that the trap function called the
panic function. However, the stack trace does not show what caused
the trap.
5 Look to see what processes were running when the system crashed by
entering the kps command.
6 Look to see what the process ID (PID) was pointing to at the time of the
crash. In this case, the PID was pointing to process 2311, which is the
inetd daemon, from the kps command output.
7 Display the preserved message buffer (pmsgbuf). Note that this buffer
contains the program counter (pc) value, which is displayed in the
following line:
va=0000000000000028, status word=0000000000000000, pc=fffffc000032972c
8 Display register 28 of the exception frame pointer (savedefp). This
register always contains the pc value. You can always obtain the pc
value from either the preserved message buffer or register 28 of the
exception frame pointer.
9 Disassemble the pc to determine its contents. The pc at the time of the
crash contained the nfs_putpage function at line 2344.
10 Disassemble the return address to determine its contents. The return
value at the time of the crash contained the ubc_invalidate function
at line 1768.
4–6 Crash Analysis Examples