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To specify a full crash dump permanently so that this setting remains in
effect after a reboot, use the patch command in dbx, as shown in the
following example:
(dbx) patch partial_dump=0
With either command, a partial_dump value of 1 specifies a partial dump.
The following example shows how to examine the state of a user program
named test1 that purposely precipitated a kernel crash with a syscall
after several recursive calls:
# dbx -k vmunix.1 vmzcore.1 /usr/proj7/test1
dbx version 5.0
Type ’help’ for help.
stopped at [boot:1890 ,0xfffffc000041ebe8] Source not available
warning: Files compiled -g3: parameter values probably wrong
(dbx) where
1
> 0 boot() ["../../../../src/kernel/arch/alpha/machdep.c":1890,
0xfffffc000041ebe8]
1 panic(0xfffffc000051e1e0, 0x8, 0x0, 0x0, 0xffffffff888c3a38)
["../../../../src/kernel/bsd/subr_prf.c":824, 0xfffffc0000281974]
2 syscall(0x2d, 0x1, 0xffffffff888c3ce0, 0x9aa1e00000000, 0x0)
["../../../../src/kernel/arch/alpha/syscall_trap.c":593, 0xfffffc0000423be4]
3 _Xsyscall(0x8, 0x3ff8010f9f8, 0x140008130, 0xaa, 0x3ffc0097b70)
["../../../../src/kernel/arch/alpha/locore.s":1409, 0xfffffc000041b0f4]
4 __syscall(0x0, 0x0, 0x0, 0x0, 0x0) [0x3ff8010f9f4]
5 justtryme(scall = 170, cpu = 0, levels = 25) ["test1.c":14,
0x120001310]
6 recurse(inbox = (...)) ["test1.c":28, 0x1200013c4]
7 recurse(inbox = (...)) ["test1.c":30, 0x120001400]
8 recurse(inbox = (...)) ["test1.c":30, 0x120001400]
9 recurse(inbox = (...)) ["test1.c":30, 0x120001400]
.
.
.
30 recurse(inbox = (...)) ["test1.c":30, 0x120001400]
31 main(argc = 3, argv = 0x11ffffd08) ["test1.c":52, 0x120001518]
(dbx) up 8
2
recurse: 30 if (r.a[2] > 0) recurse(r);
(dbx) print r
3
struct {
a={
[0] 170
[1] 0
[2] 2
[3] 0
.
.
.
(dbx) print r.a[511]
4
25
(dbx)
1 The where command displays the kernel stack followed by the user
program stack at the time of the crash. In this case, the kernel stack
has 4 activation levels; the user program stack starts with the fifth level
and includes several recursive calls.
Kernel Debugging Utilities 2–9