GDB can't insert internal breakpoint

问题

I added two breakpoints in functions of one shared library (.so) and ran gdb 7.4 and attached it to a process.

Gdb hit the breakpoint and I ran n for several steps, and gdb reported the following errors(with bold text):

(gdb) b [function name]
Breakpoint 1 at 0xf1f28a49: file ../../../../../[file name].cpp, line 167.
Breakpoint 2 at 0xf1f2dae5: file ../../../../../[file name].cpp, line 60.
warning: Multiple breakpoints were set.
Use the "delete" command to delete unwanted breakpoints.
(gdb) c
Continuing.
[New Thread 0xcaafab90 (LWP 28480)]
[Thread 0xcaafab90 (LWP 28480) exited]
[New Thread 0xcaafab90 (LWP 29558)]
[New Thread 0xc8cb6b90 (LWP 29980)]
[Switching to Thread 0xc8cb6b90 (LWP 29980)]

Breakpoint 2, [function name] (ostr=..., clientResponse=..., httpProtocol=..., >reqType=...) at ../../../../../[file name].cpp:60
60 ../../../../../[file name].cpp: No such file or directory.
in ../../../../../[file name].cpp
(gdb) ni
0xf1f2daed 60 in ../../../../../[file name].cpp
(gdb) n

Breakpoint 1, [function name] (ostr=..., clientResponse=..., httpProtocol=..., >closeConn=..., asynchResponse=..., reqType=...)
at ../../../../../[file name].cpp:167
167 in ../../../../../[file name].cpp
(gdb) n
Warning:
Cannot insert breakpoint 0.
Error accessing memory address 0x36cc6dde: Input/output error.

0xf7082771 in siglongjmp () from /lib/libc.so.6
(gdb)

This is the output from /proc/[PID]/maps:

08048000-08146000 r-xp 00000000 08:03 293876

08146000-08150000 rw-p 000fe000 08:03 293876

08150000-099c8000 rw-p 08150000 00:00 0
[heap]
c21f9000-c21fa000 ---p c21f9000 00:00 0
c21fa000-c29fa000 rwxp c21fa000 00:00 0
c29fa000-c29fb000 ---p c29fa000 00:00 0
……
f1e1b000-f1e24000 rw-p f1e1b000 00:00 0
f1e24000-f2093000 r-xp 00000000 08:03 295549
.so
f2093000-f2094000 ---p 0026f000 08:03 295549
.so
f2094000-f2098000 r--p 0026f000 08:03 295549
.so
f2098000-f209c000 rw-p 00273000 08:03 295549
.so
f209c000-f209d000 rw-p f209c000 00:00 0

My questions are:

Gdb fails to insert internal breakpoint for ni command, but why does it try to access address 0x36cc6dde if the text section is at 0xf1******?That address is not included in the output of maps as you can see.
More general question, I was told shared library starts at 0x40000000 but why this is not the case in my environment?

The shared library is compiled with -fPIC. I hide some symbol names in the traces above.

回答1:

This is probably related to http://sourceware.org/bugzilla/show_bug.cgi?id=13987. Please, could you try the latest FSF GDB HEAD (can be obtained from: git://sourceware.org/git/gdb.git).

来源：https://stackoverflow.com/questions/9564417/gdb-cant-insert-internal-breakpoint

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c++

Linux

gdb

shared-libraries

proc