| FAQ ID |
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Synopsis |
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Date |
| 3289 |
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Walking the stack by hand in a 64-bit mode OS core dump |
|
3 Jan 2001 |
Trying to walk through the stack of a Solaris 7 or Solaris 8 64-bit
core dump manually using adb, seems to result in incorrect outputs.
Using the same procedure on a 32-bit core dump from Solaris 7 or 8
gives correct results. Why is this so ? |
The header file /usr/include/sys/stack.h in Solaris 7 and 8 defines a
stack bias for 64-bit stacks. The value of this ABI offset is 2047 bytes.
This stack bias is used to differentiate between the 32-bit and 64-bit
stacks. The corresponding entry from the header file is shown below.
#define V9BIAS64 (2048-1) /* v9 abi stack bias */
So, when adb is used to manually walk through the stack frames in
64-bit crash dumps, one has to add a value of 0x7ff (which is the hex
equivalent of the decimal number 2047) to the stack pointer or frame
pointer value to obtain the correct address locations.
It is to be noted that the SPARC version 9 registers are all 64-bit
and hence one would need to use the "/J" format modifier in adb to
print the 64-bit extended word addresses rather than the "/X"
format modifier which prints only the 32-bit word addresses.
An example is given below showing the differences.
mtv-u10-1% adb -k unix.5 vmcore.5
physmem 3d935
$r
g0 0 l0 0
g1 0 l1 0
g2 0 l2 0
g3 0 l3 0
g4 0 l4 0
g5 0 l5 0
g6 0 l6 0
g7 0 l7 0
o0 0 i0 0
o1 0 i1 0
o2 0 i2 0
o3 0 i3 0
o4 0 i4 0
o5 0 i5 0
sp 10422701 panic_stack+0x3591 fp 0
o7 10046850 panicsys+0x44 i7 0
y 0
tstate: 0 (ccr=0x0, asi=0x0, pstate=0x0, cwp=0x0)
pstate: ag:0 ie:0 priv:0 am:0 pef:0 mm:0 tle:0 cle:0 mg:0 ig:0
pc 10046850 panicsys+0x44: call setjmp
npc 0
/* Using the %sp value, printing the next 16 words */
10422701/16J
panic_stack+0x3591: 10421f7100 102f696000 0
0 0 300097742e800 300097742c800
7809bbf000 300097740e800 300097c264000 300097740e800
300097c264000 2000 102f36f800 8700
200
/* Printing the %o7 register (PC value) contents results in an incorrect
address
*/
200/i
data address not found
/* Adding an offset of 7ff to the %sp and printing the next 16 words */
10422701+7ff/16J
panic_stack+0x3d90: 0 2000000448 20
4c9 2a1005f15b8 ffffffff80000000 101cef7c
0 104230d0 2a1005f0848 100526f0
78002000 30006604050 30008d8e300 10422821
10035ee0
/* This gives the correct addresses as can be verified by the %o7 register
contets */
10035ee0/i
vpanic+0xcc: call panicsys
/* Next stack frame */
10422821+7ff/16J
panic_stack+0x3eb0: 9900001605 10035e14 10035e18
0 1 2a1005f1718 0
1 100526f0 2a1005f0848 23
8 8 8 2a1005eff11
10046d48
/* The %o7 register value contents are correct again */
10046d48/i
panic+0x1c: call vpanic
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