2960S 交换机4部堆叠，其中一部交换机无故重启，交换机版本15.2(2)E5，
crash 日志如下，求帮忙分析是不是硬件故障。
Cisco IOS Software, C2960S Software (C2960S-UNIVERSALK9-M), Version 15.2(2)E5, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2016 by Cisco Systems, Inc.
Compiled Thu 02-Jun-16 01:01 by prod_rel_team
Debug Exception (Could be NULL pointer dereference) Exception (0x2000)!
SRR0 = 0x0182D1CC SRR1 = 0x00029230 SRR2 = 0x02346C1C SRR3 = 0x00029230
ESR = 0x00000000 DEAR = 0x00000000 TSR = 0x84000000 DBSR = 0x01000000
CPU Register Context:
Vector = 0x00002000 PC = 0x02346C1C MSR = 0x00029230 CR = 0x53000035
LR = 0x01D1575C CTR = 0x00000000 XER = 0xE0000014
R0 = 0x00000068 R1 = 0x047554B0 R2 = 0x00000000 R3 = 0x047554D0
R4 = 0x00000000 R5 = 0x00000010 R6 = 0x00000000 R7 = 0x00000000
R8 = 0x0000000B R9 = 0x047554D0 R10 = 0x047554F8 R11 = 0x04755520
R12 = 0x33000033 R13 = 0x00000280 R14 = 0x01DD5598 R15 = 0x00000000
R16 = 0x00000000 R17 = 0x00000000 R18 = 0x00000000 R19 = 0x00000000
R20 = 0x00000000 R21 = 0x00000000 R22 = 0x00000000 R23 = 0x00000000
R24 = 0x00000000 R25 = 0x00000009 R26 = 0x00000001 R27 = 0x00000001
R28 = 0x047554B8 R29 = 0x00000000 R30 = 0x00000001 R31 = 0x00000063
Stack trace:
PC = 0x02346C1C, SP = 0x047554B0
Frame 00: SP = 0x04755550 PC = 0x04755530
Frame 01: SP = 0x04755588 PC = 0x01DD57A0
Frame 02: SP = 0x04755590 PC = 0x0219D3C0
Frame 03: SP = 0x00000000 PC = 0x02199740