Develop Reference

Android: building a static aarch64 gdb

I am having a lot of trouble using gdbserver and gdbserver64 on Android and the companion aarch64 gdb on my host. For example, I run into issues like this, where gdb is outputting what seems to be nonsense:
(gdb) target remote :5039
Remote debugging using :5039
warning: Could not load vsyscall page because no executable was specified
try using the "file" command first.
0x0000007fa7921d2c in ?? ()
(gdb) bt
Python Exception <type 'exceptions.ImportError'> No module named gdb.frames:
#0 0x0000007fa7921d2c in ?? ()
#1 0x0000000040000600 in ?? ()
Backtrace stopped: Cannot access memory at address 0x22eee199476794f4
(gdb) c
Continuing.
Program received signal SIGSEGV, Segmentation fault.
0x0000007f87c249b4 in ?? ()
(gdb) x/4i $pc
=> 0x7f87c249b4: ldrb w8, [x0,#432]
0x7f87c249b8: cbz w8, 0x7f87c249ec
0x7f87c249bc: ldr x8, [x19,#3632]
0x7f87c249c0: ldr x9, [x8,#24]
(gdb) bt
Python Exception <type 'exceptions.ImportError'> No module named gdb.frames:
#0 0x0000007f87c249b4 in ?? ()
#1 0x0000007fa4b4fb25 in ?? ()
#2 0x0000000000000001 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) c
Continuing.
[New Thread 22374]
[New Thread 22375]
Program received signal SIGSEGV, Segmentation fault.
0x0000007f87c249b4 in ?? ()
(gdb) c
Continuing.
Program received signal SIGSEGV, Segmentation fault.
0x0000007f87c249b4 in ?? ()
This is almost impossible to use, with everything being totally unhelpful. No symbols are loaded and no backtraces are even remotely reasonable. The app is also repeatedly signaled in places that it is not signaled at when being straced or traced using a static gdb (just to name one specific problem with it).
However, I was able to use a prebuilt armv7a statically linked gdb binary to debug some 32-bit applications in an Android emulator with relative ease. I ran the static gdb in a device shell without issue. I had no trouble loading symbols and had no odd signaling problems.
I couldn't find a statically linked aarch64 gdb binary anywhere, so I tried to build one inside my aarch64 chroot. I did manage to build gdb for aarch64, and I used these configure flags:
LDFLAGS="-static" ../configure --prefix=/noprefix --enable-static --disable-shared --disable-interprocess-agent --disable-libcc1
But it is dynamically linked, which is not what I wanted.
root#gram:/opt/gdb-aarch64/noprefix/bin# file gdb
gdb: ELF 64-bit LSB shared object, ARM aarch64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, for GNU/Linux 3.7.0, BuildID[sha1]=f1a630e569467794c45b4389f510720c4342704b, not stripped
How do I build a statically linked linux aarch64 gdb?

Next step error when debugging Android kernel

I am researching Linux kernel source code on Android. So I built a debugging environment on Android emulator (the emulator based on qemu). But, when I debug the kernel using gdb, the next command always jump to error code. Here is the example:
(gdb) b vfs_write
Breakpoint 3 at 0xffffffff80383ec8: file fs/read_write.c, line 527.
(gdb) c
Continuing.
[Switching to Thread 3]
Thread 3 hit Breakpoint 3, vfs_write (file=0xffff88003aa7a600, buf=0x72f8f6490f9f "*\032_\f\220\250\364\275\345\310\023\320\022", count=1, pos=0xffff88000b7c7f18)
at fs/read_write.c:527
527 if (!(file->f_mode & FMODE_WRITE))
(gdb) list
522
523 ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
524 {
525 ssize_t ret;
526
527 if (!(file->f_mode & FMODE_WRITE))
528 return -EBADF;
529 if (!(file->f_mode & FMODE_CAN_WRITE))
530 return -EINVAL;
531 if (unlikely(!access_ok(VERIFY_READ, buf, count)))
(gdb) n
ioread8 (addr=0xffffc90000040000) at lib/iomap.c:73
73 IO_COND(addr, return inb(port), return readb(addr));
(gdb)
The breakpoint at fs/read_write.c:527. When next (n), the debugger should stop at fs/read_write.c:528 or fs/read_write.c:529. But unexpected, it jumped to lib/iomap.c:73.
Why does this problem happen?
I get the Android kernel source from
https://android.googlesource.com/kernel/goldfish
And, I checkout branch android-goldfish-4.4-dev
I built the kernel with some configs:
CONFIG_DEBUG_KERNEL=y
CONFIG_DEBUG_INFO=y
CONFIG_KGDB=y
CONFIG_FRAME_POINTER=y
\# CONFIG_DEBUG_RODATA is not set
\# CONFIG_RANDOMIZE_BASE is not set
I launched the emulator like this:
emulator -avd Pixel2XL-x86_64 -show-kernel -verbose -wipe-data -netfast -kernel arch/x86/boot/bzImage -qemu -s
The avd Pixel2XL-x86_64 is x86_64 arch, and I built the kernel as x86_64.
Someone said this is caused by GCC O2 optimize. I referenced kernel hacking: GCC optimization for better debug experience (-Og)
But, it was useless.

NDK r11b: help needed using the ndk-gdb.py debugger

Platform is Mac, Using NDK r11b, my application consists of around 8 c/c++ so files. In the past I've used ndk-gdb (sh) script via NDK r10e. the shell script is now deprecated and ndk-gdb.py is now the only option. Problem is I can't get it to work. I'm running it from my project folder as I've always done.
I've tried multiple command line options with no luck. It feels like it isn't finding my source files. It launches the application with the "Waiting for Debugger". I get to the (gdb) prompt. I've tried adding breakpoints with no luck breaking at reliable interrupt points.
I need some pointers as to how to configure and use the python version for ndk-gdb. Google has removed the documentation files and I can't find anything anywhere that suffices as a guide.
Some command lines I've tried.
ndk-gdb --launch --verbose This launches the application but blocks on Waiting for debugger
ndk-gdb will attach to a running process. ctr-c will pause the execution but a back trace bt lists a corrupt stack.
ndk-gdb --launch -t -v -p $ProjectDir I get a new interface I'm not familiar with and it states [ No Source Available ]
Any help or insight would be appreciated

Same story for me - I was able to get past "Waiting for Debugger" message for a new debugging session by issuing ndk-gdb --launch --force --nowait
but still ndk-gdb doesn't work well even with Google's NDK samples.
Only info thread command produces the actual result except of stack traces - bt, info stack and others complaints on the corrupt stack.
My target device is Nexus 5 running API 23 with latest updates.
The same binaries compiled by NDK r11b could be successfully debugged by GDB 7.7 from a previous NDK r10e.
On Windows, ndk-gdb.py fails with the following error message:
Traceback (most recent call last):
File "F:\work\android-ndk-r11b\prebuilt\windows\bin\ndk-gdb.py", line 704, in <module>
main()
File "F:\work\android-ndk-r11b\prebuilt\windows\bin\ndk-gdb.py", line 583, in main
args.props = device.get_props()
File "F:\work\android-ndk-r11b\python-packages\adb\device.py", line 459, in get_props
raise RuntimeError('invalid getprop line: "{}"'.format(line))
RuntimeError: invalid getprop line: ""
Actually, it looks like ndk-gdb.py from NDK r11b only works on Linux:
vagrant#vagrant:/vagrant/native_activity$ $ANDROID_NDK_ROOT/ndk-gdb --launch --force
WARNING: Failed to find jdb on your path, defaulting to --nowait
Redirecting gdbclient output to /tmp/gdbclient-9150
GNU gdb (GDB) 7.10
...
This GDB was configured as "x86_64-linux-gnu".
...
warning: Could not load shared library symbols for 110 libraries, e.g. /system/lib/libcutils.so.
Use the "info sharedlibrary" command to see the complete listing.
Do you need "set solib-search-path" or "set sysroot"?
0xb6c93894 in __epoll_pwait () from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
(gdb) info sources
Source files for which symbols have been read in:
Source files for which symbols will be read in on demand:
/Volumes/Android/buildbot/tmp/build/toolchain/gcc-4.9/gcc/include/unwind-arm-common.h,
/Volumes/Android/buildbot/src/android/gcc/toolchain/build/../gcc/gcc-4.9/libgcc/config/arm/pr-support.c,
/Volumes/Android/buildbot/src/android/gcc/toolchain/build/../gcc/gcc-4.9/libgcc/config/arm/libunwind.S,
/Volumes/Android/buildbot/tmp/build/toolchain/gcc-4.9/arm-linux-androideabi/armv7-a/libgcc/./unwind.h,
/Volumes/Android/buildbot/src/android/gcc/toolchain/build/../gcc/gcc-4.9/libgcc/unwind-arm-common.inc,
/Volumes/Android/buildbot/src/android/gcc/toolchain/build/../gcc/gcc-4.9/libgcc/config/arm/unwind-arm.c,
/Users/mike/android-ndk-r11b/sources/android/native_app_glue/android_native_app_glue.c,
/vagrant/native_activity/jni/main.c
Basic commands is working correctly:
(gdb) bt
#0 0xb6c93894 in __epoll_pwait () from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
#1 0xb6c6ce72 in epoll_pwait () from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
#2 0xb6c6ce80 in epoll_wait () from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
#3 0xb6ebfc5a in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) info thread
Id Target Id Frame
11 Thread 28735 0xb6c6a5e4 in syscall ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
10 Thread 28733 0xb6c93894 in __epoll_pwait ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
9 Thread 28721 0xb6c939bc in __ioctl ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
8 Thread 28720 0xb6c939bc in __ioctl ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
7 Thread 28719 0xb6c6a5e4 in syscall ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
6 Thread 28718 0xb6c6a5e4 in syscall ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
5 Thread 28717 0xb6c6a5e4 in syscall ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
4 Thread 28716 0xb6c6a5e4 in syscall ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
3 Thread 28715 0xb6c94948 in recvmsg ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
2 Thread 28714 0xb6c93b68 in __rt_sigtimedwait ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so
* 1 Thread 28709 0xb6c93894 in __epoll_pwait ()
from /vagrant/native_activity/obj/local/armeabi-v7a/system/lib/libc.so

This issue was posted to the https://github.com/android-ndk/ndk/issues site that Mikhail provided. The issue was assigned and claimed fixed: Resolution will be propagated in NDK r11c;
https://github.com/android-ndk/ndk/issues/51
additionally I updated to R11c. everything is now working

How to Debug native code using ndk-gdb

This is what I am getting after running ndk-gdb according to many tutorials when it links to you to (gdb) server you have to type continue but what after that how to debug the code there after. In my case it displays Continuing and remain like this. WHat i have to do further I am totally clueless.
Arathore#chd-arathore-AND /cygdrive/d/All_Work/All_ARathore/All_Workspace_Practice/ndkfoo
$ /cygdrive/d/All_Required_Stuff/Android/android-ndk-r8e/ndk-gdb --verbose --adb=/cygdrive/D/All_Required_Stuff/Android/android-sdk-windows/platform-tools/adb.exe
Android NDK installation path: /cygdrive/d/All_Required_Stuff/Android/android-ndk-r8e
Using specific adb command: /cygdrive/D/All_Required_Stuff/Android/android-sdk-windows/platform-tools/adb.exe
ADB version found: Android Debug Bridge version 1.0.31
Using ADB flags:
Using auto-detected project path: .
Found package name: com.example.ndkfoo
/cygdrive/d/All_Required_Stuff/Android/android-ndk-r8e/build/core/add-application.mk:128: Android NDK: WARNING: APP_PLATFORM android-14 is larger than android:minSdkVersion 8 in /cygdrive/d/All_Work/All_ARathore/All_Workspace_Practice/ndkfoo/AndroidManifest.xml
ABIs targetted by application: armeabi
Device API Level: 17
Device CPU ABIs: armeabi-v7a armeabi
Compatible device ABI: armeabi
/cygdrive/d/All_Required_Stuff/Android/android-ndk-r8e/build/core/add-application.mk:128: Android NDK: WARNING: APP_PLATFORM android-14 is larger than android:minSdkVersion 8 in /cygdrive/d/All_Work/All_ARathore/All_Workspace_Practice/ndkfoo/AndroidManifest.xml
Using gdb setup init: /cygdrive/d/All_Work/All_ARathore/All_Workspace_Practice/ndkfoo/libs/armeabi/gdb.setup
/cygdrive/d/All_Required_Stuff/Android/android-ndk-r8e/build/core/add-application.mk:128: Android NDK: WARNING: APP_PLATFORM android-14 is larger than android:minSdkVersion 8 in /cygdrive/d/All_Work/All_ARathore/All_Workspace_Practice/ndkfoo/AndroidManifest.xml
Using toolchain prefix: /cygdrive/d/All_Required_Stuff/Android/android-ndk-r8e/toolchains/arm-linux-androideabi-4.6/prebuilt/windows/bin/arm-linux-androideabi-
/cygdrive/d/All_Required_Stuff/Android/android-ndk-r8e/build/core/add-application.mk:128: Android NDK: WARNING: APP_PLATFORM android-14 is larger than android:minSdkVersion 8 in /cygdrive/d/All_Work/All_ARathore/All_Workspace_Practice/ndkfoo/AndroidManifest.xml
Using app out directory: ./obj/local/armeabi
Found debuggable flag: true
Found device gdbserver: /data/data/com.example.ndkfoo/lib/gdbserver
Found data directory: '/data/data/com.example.ndkfoo'
Found running PID: 1106
Launched gdbserver succesfully.
Setup network redirection
## COMMAND: adb_cmd shell run-as com.example.ndkfoo lib/gdbserver +debug-socket --attach 1106
## COMMAND: adb_cmd forward tcp:5039 localfilesystem:/data/data/com.example.ndkfoo/debug-socket
## COMMAND: adb_cmd pull /system/bin/app_process obj/local/armeabi/app_process
Attached; pid = 1106
Listening on Unix socket debug-socket
99 KB/s (9592 bytes in 0.093s)
Pulled app_process from device/emulator.
## COMMAND: adb_cmd pull /system/bin/linker obj/local/armeabi/linker
54 KB/s (63240 bytes in 1.140s)
Pulled linker from device/emulator.
## COMMAND: adb_cmd pull /system/lib/libc.so obj/local/armeabi/libc.so
75 KB/s (297604 bytes in 3.828s)
Pulled libc.so from device/emulator.
GNU gdb (GDB) 7.3.1-gg2
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "--host=i586-pc-mingw32msvc --target=arm-linux-android".
For bug reporting instructions, please see:
<http://source.android.com/source/report-bugs.html>.
Remote debugging from host 0.0.0.0
libthread_db:td_ta_new: Probing system for platform bug.
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1147/task/1147/status
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1106/task/1106/status
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1106/task/1109/status
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1106/task/1111/status
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1106/task/1112/status
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1106/task/1113/status
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1106/task/1114/status
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1106/task/1115/status
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1106/task/1116/status
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1106/task/1117/status
libthread_db:_get_task_permitted_caps: Found CapPerm of 0 in /proc/1106/task/1118/status
libthread_db:td_ta_new: Victory: We can debug theads!
0x40037ebc in epoll_wait () from D:/All_Work/All_ARathore/All_Workspace_Practice/ndkfoo/obj/local/armeabi/libc.so
warning: Could not load shared library symbols for 72 libraries, e.g. libstdc++.so.
Use the "info sharedlibrary" command to see the complete listing.
Do you need "set solib-search-path" or "set sysroot"?
warning: Breakpoint address adjusted from 0x40005a53 to 0x40005a52.
(gdb) continue
Continuing.
How to debug?
According to the ndk-Docs
You can set breakpoints with 'b <location>' and resume execution with 'c'
(for 'continue'). See the GDB manual for a list of commands.
How to make this happen.

The commands are the same as in gdb. A basic primer:
Set a breakpoint by entering b <function name> or b <file>:<line number>
step into functions by typing s
go to next line by typing n
continue execution with c
print a variable or expression value with print <exp>
repeat the last typed command by just hitting enter
You can find much more comprehensive gdb tutorials online. I personally have a gdb cheatsheet printed out and posted on my wall. This should be enough to get you started.

this tutorial will show you exactly how to debugging with ndk-gdb in eclipse.

Not able to hit the break point in ndk-gdb in Android

Development Environment:
NDK: r7
SDK & Tools: r15
AVD: GB2.3.3, API Level 10
I wrote a test application in which thread will be launched in the native. I Kept a break point in the thread. (Intially when i tried on Galaxy S2 i was getting an error, "Thread debugging not supported in this Platform". So i created an AVD 2.3.3 Level 10).
After this i was getting an error like this
#0 0xafd0c51c in epoll_wait () from /Volumes/SecureCode/webos/rta/android/obj/local/armeabi/libc.so
#1 0xa81216a6 in ?? ()
I googled and found this Solution (Link Here).
I followed the guide lines there
$ adb pull /system/lib lib
$ ndk-gdb
...
(gdb) set solib-search-path lib
But after this also I am not able to hit the break point. I am still getting stuck at this poll_wait() and not moving forward.
D:\EclipseTestWorkspace\CallbackJava>sh
sh-4.1$ ndk-gdb --force --start --verbose
Android NDK installation path: /cygdrive/c/Android/android-ndk
Using default adb command: /cygdrive/c/Android/android-sdk-windows/platform-tools/adb
ADB version found: Android Debug Bridge version 1.0.29
Using final ADB command: '/cygdrive/c/Android/android-sdk-windows/platform-tools/adb'
Using auto-detected project path: .
Found package name: com.callback
ABIs targetted by application: armeabi
Device API Level: 10
Device CPU ABI: armeabi
Compatible device ABI: armeabi
Found debuggable flag: true
Found device gdbserver: /data/data/com.callback/lib/gdbserver
Using gdb setup init: ./libs/armeabi/gdb.setup
Using toolchain prefix: /cygdrive/c/Android/android-ndk/toolchains/arm-linux-androideabi-4.4.3/prebuilt/windows/bin/arm-linux-androideabi-
Using app out directory: ./obj/local/armeabi
Found data directory: '/data/data/com.callback'
Found first launchable activity: .CallbackJavaActivity
Launching activity: com.callback/.CallbackJavaActivity
## COMMAND: /cygdrive/c/Android/android-sdk-windows/platform-tools/adb shell am start -n com.callback/.CallbackJavaActivity
Starting: Intent { cmp=com.callback/.CallbackJavaActivity }
## COMMAND: /cygdrive/c/Android/android-sdk-windows/platform-tools/adb shell sleep 2
Found running PID: 352
Launched gdbserver succesfully.
## COMMAND: /cygdrive/c/Android/android-sdk-windows/platform-tools/adb shell run-as com.callback lib/gdbserver +debug-socket --attach 352
Setup network redirection
## COMMAND: /cygdrive/c/Android/android-sdk-windows/platform-tools/adb forward tcp:5039 localfilesystem:/data/data/com.callback/debug-socket
## COMMAND: /cygdrive/c/Android/android-sdk-windows/platform-tools/adb pull /system/bin/app_process obj/local/armeabi/app_process
Attached; pid = 352
Listening on sockaddr socket debug-socket
19 KB/s (5660 bytes in 0.281s)
Pulled app_process from device/emulator.
## COMMAND: /cygdrive/c/Android/android-sdk-windows/platform-tools/adb pull /system/lib/libc.so obj/local/armeabi/libc.so
80 KB/s (273868 bytes in 3.325s)
Pulled libc.so from device/emulator.
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 "--host=i586-mingw32msvc --target=arm-elf-linux".
(no debugging symbols found)
Error while mapping shared library sections:
/system/bin/linker: No such file or directory.
----- So many similar errors -----
Error while mapping shared library sections:
gralloc.default.so: No such file or directory.
(no debugging symbols found)
warning: Unable to find dynamic linker breakpoint function.
GDB will be unable to debug shared library initializers
and track explicitly loaded dynamic code.
warning: shared library handler failed to enable breakpoint
0xafd0c51c in epoll_wait () from D:/EclipseTestWorkspace/CallbackJava/obj/local/armeabi/libc.so
(gdb) set solib-search-path lib
Error while mapping shared library sections:
/system/bin/linker: No such file or directory.
Error while mapping shared library sections:
gralloc.default.so: No such file or directory.
Symbol file not found for /system/bin/linker
Reading symbols from D:\EclipseTestWorkspace\CallbackJava/lib/libc.so...(no debugging symbols found)...done.
Loaded symbols for D:\EclipseTestWorkspace\CallbackJava/lib/libc.so
----- So many similar errors -----
Loaded symbols for D:\EclipseTestWorkspace\CallbackJava/lib/libwebcore.so
Symbol file not found for gralloc.default.so
(gdb) file ./libs/armeabi/libcallbacks.so
A program is being debugged already.
Are you sure you want to change the file? (y or n) y
Reading symbols from D:\EclipseTestWorkspace\CallbackJava/./libs/armeabi/libcallbacks.so...(no debugging symbols found)...done.
(gdb) file ./obj/local/armeabi/libcallbacks.so
A program is being debugged already.
Are you sure you want to change the file? (y or n) y
Reading symbols from D:\EclipseTestWorkspace\CallbackJava/./obj/local/armeabi/libcallbacks.so...done.
(gdb) break callbacks_java.cpp:appcallback_register
Breakpoint 1 at 0x1a64: file D:/EclipseTestWorkspace/CallbackJava/jni/callbacks_java.cpp, line 419.
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y 0x00001a64 in appcallback_register at D:/EclipseTestWorkspace/CallbackJava/jni/callbacks_java.cpp:419
(gdb) where
#0 0xafd0c51c in epoll_wait () from D:\EclipseTestWorkspace\CallbackJava/lib/libc.so
#1 0xa81211b4 in android::Looper::pollInner () from D:\EclipseTestWorkspace\CallbackJava/lib/libutils.so
#2 0x00000000 in ?? ()
(gdb) where
#0 0xafd0c51c in epoll_wait () from D:\EclipseTestWorkspace\CallbackJava/lib/libc.so
#1 0xa81211b4 in android::Looper::pollInner () from D:\EclipseTestWorkspace\CallbackJava/lib/libutils.so
#2 0x00000000 in ?? ()
(gdb) c
Continuing.
Warning:
Cannot insert breakpoint 1.
Error accessing memory address 0x1a64: Input/output error.
(gdb)
Which i would like to concentrate on main part as
(gdb) file ./libs/armeabi/libcallbacks.so
A program is being debugged already.
Are you sure you want to change the file? (y or n) y
Reading symbols from D:\EclipseTestWorkspace\CallbackJava/./libs/armeabi/libcallbacks.so...(no debugging symbols found)...done.
(gdb) file ./obj/local/armeabi/libcallbacks.so
A program is being debugged already.
Are you sure you want to change the file? (y or n) y
Reading symbols from D:\EclipseTestWorkspace\CallbackJava/./obj/local/armeabi/libcallbacks.so...done.
(gdb) break callbacks_java.cpp:appcallback_register
Breakpoint 1 at 0x1a64: file D:/EclipseTestWorkspace/CallbackJava/jni/callbacks_java.cpp, line 419.
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y 0x00001a64 in appcallback_register at D:/EclipseTestWorkspace/CallbackJava/jni/callbacks_java.cpp:419
(gdb) where
#0 0xafd0c51c in epoll_wait () from D:\EclipseTestWorkspace\CallbackJava/lib/libc.so
#1 0xa81211b4 in android::Looper::pollInner () from D:\EclipseTestWorkspace\CallbackJava/lib/libutils.so
#2 0x00000000 in ?? ()
(gdb) where
#0 0xafd0c51c in epoll_wait () from D:\EclipseTestWorkspace\CallbackJava/lib/libc.so
#1 0xa81211b4 in android::Looper::pollInner () from D:\EclipseTestWorkspace\CallbackJava/lib/libutils.so
#2 0x00000000 in ?? ()
(gdb) c
Continuing.
Warning:
Cannot insert breakpoint 1.
Error accessing memory address 0x1a64: Input/output error.
(gdb)
So from the last error what i understand is its considering the absolute address 0x1a64. Its not considering the relative address (runtime address), so not able to hit the break point. and also its getting stuck at the epoll_wait () , not moving further.
Will any one please help me how can I proceed further?
Thanks & Regards,
SSuman185

You could try debugging in Eclipse with DS-5 CE plugin. Tutorial how to install and setup it you can find here http://forums.arm.com/index.php?/topic/15575-arm-ds-5-tutorial-for-android/ (last post is how to make it work on SGS2).
I know that is not an exact answer to your question, but if you need NDK debugging on SGS2 you might want to try it, also it's for Eclipse, not a command line gdb (but who could ever prefer command-line debugging instead of debugging in IDE??)
PS. DS-5 CE is a first NDK debugging tool that worked for me with SGS2 (it's not perfect - possibly because of bugs/limitations in SGS2 - but at least works).