Here's the snapshot of the session (I've attached the code for the appln "thread" I'm running). I'm building it w/ gcc -Wall -D_REENTRANT -g -o thread main.c -lpthread). # ls -l /lib64/libpthread libpthread-2.3.6.so libpthread.so.0 # gdb64 thread GNU gdb 6.6 Copyright (C) 2006 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "x86_64-unknown-linux-gnu"... Using host libthread_db library "/lib64/libthread_db.so.1". (gdb) break main Breakpoint 1 at 0x4006e0: file main.c, line 29. (gdb) r Starting program: thread Failed to read a valid object file image from memory. Breakpoint 1, main () at main.c:29 29 main.c: No such file or directory. in main.c (gdb) n 30 in main.c (gdb) n 29 in main.c (gdb) Thread ID1075841376: X is now 1. Thread ID1075841376: X is now 2. Thread ID1075841376: X is now 3. Thread ID1075841376: X is now 4. Thread ID1075841376: X is now 5. Thread ID1075841376: X is now 6. Thread ID1075841376: X is now 7. Thread ID1075841376: X is now 8. Thread ID1075841376: X is now 9. Thread ID1075841376: X is now 10. 30 in main.c (gdb) Thread ID1075841376: X is now 11. Thread ID1075841376: X is now 12. Thread ID1075841376: X is now 13. Thread ID1075841376: X is now 14. Thread ID1075841376: X is now 15. Thread ID1075841376: X is now 16. Thread ID1075841376: X is now 17. Thread ID1075841376: X is now 18. Thread ID1075841376: X is now 19. Thread ID1075841376: X is now 20. Thread ID1075841376: X is now 21. Thread ID1075841376: X is now 22. Thread ID1075841376: X is now 23. Thread ID1075841376: X is now 24. Thread ID1075841376: X is now 25. 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Thread ID1075841376: X is now 84. Thread ID1075841376: X is now 85. Thread ID1075841376: X is now 86. Thread ID1075841376: X is now 87. Thread ID1075841376: X is now 88. Thread ID1075841376: X is now 89. Thread ID1075841376: X is now 90. Thread ID1075841376: X is now 91. Thread ID1075841376: X is now 92. Thread ID1075841376: X is now 93. Thread ID1075841376: X is now 94. Thread ID1075841376: X is now 95. Thread ID1075841376: X is now 96. Thread ID1075841376: X is now 97. Thread ID1075841376: X is now 98. Thread ID1075841376: X is now 99. Thread ID1075841376: X is now 100. Thread ID1075841376: X is now 101. Thread ID1075841376: X is now 102. Thread ID1075841376: X is now 103. Thread ID1075841376: X is now 104. Thread ID1075841376: X is now 105. 29 in main.c (gdb) info threads (gdb) n Thread ID1077942624: X is now 106. Thread ID1077942624: X is now 107. Thread ID1077942624: X is now 108. Thread ID1077942624: X is now 109. Thread ID1077942624: X is now 110. Thread ID1077942624: X is now 111. Thread ID1077942624: X is now 112. Thread ID1077942624: X is now 113. 30 in main.c (gdb) n Thread ID1077942624: X is now 114. Thread ID1077942624: X is now 115. Thread ID1077942624: X is now 116. Thread ID1077942624: X is now 117. Thread ID1077942624: X is now 118. Thread ID1077942624: X is now 119. Thread ID1077942624: X is now 120. Thread ID1077942624: X is now 121. Thread ID1077942624: X is now 122. Thread ID1077942624: X is now 123. Thread ID1077942624: X is now 124. Thread ID1077942624: X is now 125. Thread ID1077942624: X is now 126. Thread ID1077942624: X is now 127. Thread ID1077942624: X is now 128. Thread ID1077942624: X is now 129. Thread ID1077942624: X is now 130. Thread ID1077942624: X is now 131. Thread ID1077942624: X is now 132. Thread ID1077942624: X is now 133. Thread ID1077942624: X is now 134. Thread ID1077942624: X is now 135. Thread ID1077942624: X is now 136. Thread ID1075841376: X is now 137. Thread ID1075841376: X is now 138. Thread ID1075841376: X is now 139. Thread ID1075841376: X is now 140. Thread ID1075841376: X is now 141. Thread ID1075841376: X is now 142. Thread ID1075841376: X is now 143. Thread ID1077942624: X is now 144. 29 in main.c (gdb) n Thread ID1080043872: X is now 145. Thread ID1080043872: X is now 146. Thread ID1080043872: X is now 147. Thread ID1080043872: X is now 148. Thread ID1080043872: X is now 149. Thread ID1080043872: X is now 150. 30 in main.c (gdb) Thread ID1080043872: X is now 151. Thread ID1080043872: X is now 152. Thread ID1080043872: X is now 153. Thread ID1077942624: X is now 154. Thread ID1077942624: X is now 155. Thread ID1077942624: X is now 156. Thread ID1077942624: X is now 157. Thread ID1077942624: X is now 158. Thread ID1077942624: X is now 159. Thread ID1077942624: X is now 160. Thread ID1077942624: X is now 161. Thread ID1080043872: X is now 162. Thread ID1080043872: X is now 163. Thread ID1080043872: X is now 164. Thread ID1080043872: X is now 165. Thread ID1080043872: X is now 166. Thread ID1080043872: X is now 167. Thread ID1080043872: X is now 168. Thread ID1080043872: X is now 169. Thread ID1080043872: X is now 170. Thread ID1080043872: X is now 171. Thread ID1080043872: X is now 172. Thread ID1080043872: X is now 173. Thread ID1080043872: X is now 174. Thread ID1080043872: X is now 175. Thread ID1080043872: X is now 176. Thread ID1080043872: X is now 177. Thread ID1080043872: X is now 178. Thread ID1080043872: X is now 179. 29 in main.c (gdb) info threads (gdb) thread 2 Thread ID 2 not known. (gdb) thread 1 Thread ID 1 not known. (gdb) thread 1080043872 Thread ID 1080043872 not known. (gdb) info threads On Wed, Jun 11, 2008 at 7:58 AM, Doug Evans wrote: > On Wed, Jun 11, 2008 at 12:19 AM, Srinivas Murthy wrote: >> Hi, >> I have the following setup: >> gdb6.6 built using a 64b glibc w/ nptl enabled >> 64b glibc - 2.3.6 (nptl enabled) >> >> When I use gdb on a sample multi-threaded (nptl) app, I cant get any >> thread specific gdb cmds to work. >> >> For ex. info threads shows only one thread (the main thread). >> >> Any idea what might be going wrong? > > Unlikely, but one thing that could explain this is the glibc you're > using is a hand-made one installed in some place other than /lib64. > gdb will only look for libthread_db in a few specific places. > > A copy of the session log from the start up until the error could help > diagnosis. >