kgdb bt 跟 dump_stack() 差异

shihyu

nswcfd 发表于 2015-10-12 19:08
以下高亮部分是有区别的地方，可以发现，这些地方都没有栈的指针。
这些信息应该是gdb自己添加进去的。

...

请问怎么判断有没有栈的指针？ 从代码看出来吗？


我是用 android emulator goldfish kernel 3.4

1. CONFIG_EXPERIMENTAL=y
   
2. CONFIG_SYSVIPC=y
   
3. CONFIG_IKCONFIG=y
   
4. CONFIG_IKCONFIG_PROC=y
   
5. CONFIG_LOG_BUF_SHIFT=16
   
6. CONFIG_CGROUPS=y
   
7. CONFIG_CGROUP_DEBUG=y
   
8. CONFIG_CGROUP_FREEZER=y
   
9. CONFIG_CGROUP_CPUACCT=y
   
10. CONFIG_RESOURCE_COUNTERS=y
    
11. CONFIG_CGROUP_SCHED=y
    
12. CONFIG_RT_GROUP_SCHED=y
    
13. # CONFIG_UTS_NS is not set
    
14. # CONFIG_IPC_NS is not set
    
15. # CONFIG_USER_NS is not set
    
16. # CONFIG_PID_NS is not set
    
17. # CONFIG_NET_NS is not set
    
18. CONFIG_BLK_DEV_INITRD=y
    
19. CONFIG_CC_OPTIMIZE_FOR_SIZE=y
    
20. CONFIG_SLAB=y
    
21. # CONFIG_BLK_DEV_BSG is not set
    
22. CONFIG_ARCH_GOLDFISH=y
    
23. CONFIG_MACH_GOLDFISH=y
    
24. CONFIG_NO_HZ=y
    
25. CONFIG_HIGH_RES_TIMERS=y
    
26. CONFIG_PREEMPT=y
    
27. CONFIG_AEABI=y
    
28. # CONFIG_OABI_COMPAT is not set
    
29. CONFIG_ZBOOT_ROM_TEXT=0x0
    
30. CONFIG_ZBOOT_ROM_BSS=0x0
    
31. CONFIG_VFP=y
    
32. # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
    
33. CONFIG_BINFMT_MISC=y
    
34. CONFIG_NET=y
    
35. CONFIG_PACKET=y
    
36. CONFIG_UNIX=y
    
37. CONFIG_NET_KEY=y
    
38. CONFIG_INET=y
    
39. CONFIG_IP_MULTICAST=y
    
40. CONFIG_IP_ADVANCED_ROUTER=y
    
41. CONFIG_IP_MULTIPLE_TABLES=y
    
42. CONFIG_IP_PNP=y
    
43. CONFIG_IP_PNP_DHCP=y
    
44. CONFIG_IP_PNP_BOOTP=y
    
45. CONFIG_IP_MROUTE=y
    
46. CONFIG_IP_PIMSM_V1=y
    
47. CONFIG_IP_PIMSM_V2=y
    
48. CONFIG_SYN_COOKIES=y
    
49. CONFIG_INET_ESP=y
    
50. # CONFIG_INET_XFRM_MODE_BEET is not set
    
51. # CONFIG_INET_LRO is not set
    
52. # CONFIG_INET_DIAG is not set
    
53. CONFIG_IPV6_MULTIPLE_TABLES=y
    
54. CONFIG_NETFILTER=y
    
55. # CONFIG_BRIDGE_NETFILTER is not set
    
56. CONFIG_NF_CONNTRACK=y
    
57. CONFIG_NF_CONNTRACK_EVENTS=y
    
58. CONFIG_NF_CT_PROTO_DCCP=y
    
59. CONFIG_NF_CT_PROTO_SCTP=y
    
60. CONFIG_NF_CT_PROTO_UDPLITE=y
    
61. CONFIG_NF_CONNTRACK_AMANDA=y
    
62. CONFIG_NF_CONNTRACK_FTP=y
    
63. CONFIG_NF_CONNTRACK_H323=y
    
64. CONFIG_NF_CONNTRACK_IRC=y
    
65. CONFIG_NF_CONNTRACK_NETBIOS_NS=y
    
66. CONFIG_NF_CONNTRACK_PPTP=y
    
67. CONFIG_NF_CONNTRACK_SANE=y
    
68. CONFIG_NF_CONNTRACK_TFTP=y
    
69. CONFIG_NF_CT_NETLINK=y
    
70. CONFIG_NETFILTER_TPROXY=y
    
71. CONFIG_NETFILTER_XT_TARGET_CLASSIFY=y
    
72. CONFIG_NETFILTER_XT_TARGET_CONNMARK=y
    
73. CONFIG_NETFILTER_XT_TARGET_IDLETIMER=y
    
74. CONFIG_NETFILTER_XT_TARGET_MARK=y
    
75. CONFIG_NETFILTER_XT_TARGET_NFLOG=y
    
76. CONFIG_NETFILTER_XT_TARGET_NFQUEUE=y
    
77. CONFIG_NETFILTER_XT_TARGET_TPROXY=y
    
78. CONFIG_NETFILTER_XT_TARGET_TRACE=y
    
79. CONFIG_NETFILTER_XT_MATCH_COMMENT=y
    
80. CONFIG_NETFILTER_XT_MATCH_CONNBYTES=y
    
81. CONFIG_NETFILTER_XT_MATCH_CONNLIMIT=y
    
82. CONFIG_NETFILTER_XT_MATCH_CONNMARK=y
    
83. CONFIG_NETFILTER_XT_MATCH_CONNTRACK=y
    
84. CONFIG_NETFILTER_XT_MATCH_HASHLIMIT=y
    
85. CONFIG_NETFILTER_XT_MATCH_HELPER=y
    
86. CONFIG_NETFILTER_XT_MATCH_IPRANGE=y
    
87. CONFIG_NETFILTER_XT_MATCH_LENGTH=y
    
88. CONFIG_NETFILTER_XT_MATCH_LIMIT=y
    
89. CONFIG_NETFILTER_XT_MATCH_MAC=y
    
90. CONFIG_NETFILTER_XT_MATCH_MARK=y
    
91. CONFIG_NETFILTER_XT_MATCH_POLICY=y
    
92. CONFIG_NETFILTER_XT_MATCH_PKTTYPE=y
    
93. CONFIG_NETFILTER_XT_MATCH_QTAGUID=y
    
94. CONFIG_NETFILTER_XT_MATCH_QUOTA=y
    
95. CONFIG_NETFILTER_XT_MATCH_QUOTA2=y
    
96. CONFIG_NETFILTER_XT_MATCH_QUOTA2_LOG=y
    
97. CONFIG_NETFILTER_XT_MATCH_SOCKET=y
    
98. CONFIG_NETFILTER_XT_MATCH_STATE=y
    
99. CONFIG_NETFILTER_XT_MATCH_STATISTIC=y
    
100. CONFIG_NETFILTER_XT_MATCH_STRING=y
     
101. CONFIG_NETFILTER_XT_MATCH_TIME=y
     
102. CONFIG_NETFILTER_XT_MATCH_U32=y
     
103. CONFIG_NF_CONNTRACK_IPV4=y
     
104. CONFIG_IP_NF_IPTABLES=y
     
105. CONFIG_IP_NF_MATCH_AH=y
     
106. CONFIG_IP_NF_MATCH_ECN=y
     
107. CONFIG_IP_NF_MATCH_TTL=y
     
108. CONFIG_IP_NF_FILTER=y
     
109. CONFIG_IP_NF_TARGET_REJECT=y
     
110. CONFIG_IP_NF_TARGET_REJECT_SKERR=y
     
111. CONFIG_NF_NAT=y
     
112. CONFIG_IP_NF_TARGET_MASQUERADE=y
     
113. CONFIG_IP_NF_TARGET_NETMAP=y
     
114. CONFIG_IP_NF_TARGET_REDIRECT=y
     
115. CONFIG_IP_NF_MANGLE=y
     
116. CONFIG_IP_NF_RAW=y
     
117. CONFIG_IP_NF_ARPTABLES=y
     
118. CONFIG_IP_NF_ARPFILTER=y
     
119. CONFIG_IP_NF_ARP_MANGLE=y
     
120. CONFIG_NF_CONNTRACK_IPV6=y
     
121. CONFIG_IP6_NF_IPTABLES=y
     
122. CONFIG_IP6_NF_FILTER=y
     
123. CONFIG_IP6_NF_TARGET_REJECT=y
     
124. CONFIG_IP6_NF_TARGET_REJECT_SKERR=y
     
125. CONFIG_IP6_NF_MANGLE=y
     
126. CONFIG_IP6_NF_RAW=y
     
127. CONFIG_BRIDGE=y
     
128. CONFIG_VLAN_8021Q=y
     
129. CONFIG_CONNECTOR=y
     
130. CONFIG_MTD=y
     
131. CONFIG_MTD_CHAR=y
     
132. CONFIG_MTD_BLOCK=y
     
133. CONFIG_MTD_GOLDFISH_NAND=y
     
134. CONFIG_BLK_DEV_LOOP=y
     
135. CONFIG_BLK_DEV_NBD=y
     
136. CONFIG_BLK_DEV_RAM=y
     
137. CONFIG_BLK_DEV_RAM_SIZE=8192
     
138. CONFIG_QEMU_PIPE=y
     
139. CONFIG_QEMU_TRACE=y
     
140. CONFIG_MD=y
     
141. CONFIG_BLK_DEV_DM=y
     
142. CONFIG_DM_DEBUG=y
     
143. CONFIG_DM_CRYPT=y
     
144. CONFIG_DM_UEVENT=y
     
145. CONFIG_NETDEVICES=y
     
146. CONFIG_TUN=y
     
147. CONFIG_SMC91X=y
     
148. CONFIG_INPUT_EVDEV=y
     
149. CONFIG_KEYBOARD_GOLDFISH_EVENTS=y
     
150. # CONFIG_INPUT_MOUSE is not set
     
151. CONFIG_INPUT_MISC=y
     
152. # CONFIG_SERIO_SERPORT is not set
     
153. # CONFIG_LEGACY_PTYS is not set
     
154. CONFIG_GOLDFISH_TTY=y
     
155. CONFIG_POWER_SUPPLY=y
     
156. CONFIG_BATTERY_GOLDFISH=y
     
157. # CONFIG_HWMON is not set
     
158. CONFIG_FB=y
     
159. CONFIG_FB_MODE_HELPERS=y
     
160. CONFIG_FB_TILEBLITTING=y
     
161. CONFIG_FB_GOLDFISH=y
     
162. CONFIG_MMC=y
     
163. CONFIG_MMC_GOLDFISH=y
     
164. CONFIG_RTC_CLASS=y
     
165. CONFIG_RTC_DRV_GOLDFISH=y
     
166. CONFIG_STAGING=y
     
167. CONFIG_ANDROID=y
     
168. CONFIG_ANDROID_BINDER_IPC=y
     
169. CONFIG_ASHMEM=y
     
170. CONFIG_ANDROID_LOGGER=y
     
171. CONFIG_ANDROID_LOW_MEMORY_KILLER=y
     
172. CONFIG_ANDROID_INTF_ALARM_DEV=y
     
173. CONFIG_EXT4_FS=y
     
174. CONFIG_EXT4_FS_SECURITY=y
     
175. CONFIG_FUSE_FS=y
     
176. CONFIG_MSDOS_FS=y
     
177. CONFIG_VFAT_FS=y
     
178. CONFIG_TMPFS=y
     
179. CONFIG_YAFFS_FS=y
     
180. CONFIG_NFSD=y
     
181. CONFIG_NFSD_V3=y
     
182. CONFIG_NLS_CODEPAGE_437=y
     
183. CONFIG_NLS_ISO8859_1=y
     
184. CONFIG_MAGIC_SYSRQ=y
     
185. CONFIG_DEBUG_KERNEL=y
     
186. CONFIG_SCHEDSTATS=y
     
187. CONFIG_SCHED_TRACER=y
     
188. CONFIG_BLK_DEV_IO_TRACE=y
     
189. CONFIG_CRYPTO_ECB=y
     
190. CONFIG_CRYPTO_PCBC=y
     
191. CONFIG_CRYPTO_SHA256=y
     
192. CONFIG_CRYPTO_AES=y
     
193. CONFIG_CRYPTO_TWOFISH=y
     
194. # CONFIG_CRYPTO_ANSI_CPRNG is not set
     

复制代码

nswcfd

不是，看bt的输出。注意7楼黄色行和蓝色行的区别。
#0  lowmem_shrink (s=<optimized out>, sc=0xec923c84) at drivers/staging/android/lowmemorykiller.c:89 */
#1 【0xc00a0374 in】 do_shrinker_shrink (nr_to_scan=0, sc=0xec923d78, shrinker=0xc0518488 <lowmem_shrinker> at mm/vmscan.c:277

lowmem_shrink前面没有0x.... in（【】里的部分），而do_shrink_shrink有。
lowmem_shrink没有出现在dump_stack里面。

PS1，只有配置文件的话，还是看不出来实际的gcc选项。能否参考10楼给出实际的gcc命令行？

PS2，kgdb的bt内容是命中某个breakpoint之后结果（比如这里在lowmem_shrink设置了断点），还是一步一步step in之后的结果（例如从do_page_falut设断点后命中，然后单步调试到lowmem_shrink）？