thread debugging with gdb

[Miles Bintz]

I'm encountering a problem when debugging threads with gdb.  The problem
is similar to others I've seen on the mailing list but I've either made
sure I'm not making the same mistakes (correct libthread_db, for
example) or they're so old, I can't imagine the bugs are still relevant.
 
I'm running uclibc 0.9.29 for ARM.  gdb 6.7.1 was compiled and linked
against this uclibc.

Anyhoo, I think the root of my problem has to do with the following
warning:
"warning: Cannot initialize thread debugging library: generic error"
 
Also, GDB keeps trapping SIG32 unless I do a 'handle SIG32 nostop' --
but I get the impression I shouldn't have to do that.

Any idea what I could be doing wrong?


Runtime output:

'ps' shows about 10-11 threads running but 'info threads' in gdb only
shows 2.

# ps
...
  338 0         13588 S   gdb --args ./bin/app 
  339 0          3056 T   ./bin/app 
  342 0          3056 T   ./bin/app 
  343 0          3056 T   ./bin/app 
  344 0          3056 T   ./bin/app 
  345 0          3056 T   ./bin/app 
  346 0          3056 T   ./bin/app 
  347 0          3056 T   ./bin/app 
  348 0          3056 T   ./bin/app 
  349 0          3056 T   ./bin/app 
  350 0          3056 T   ./bin/app 
...

GNU gdb 6.7.1
Copyright (C) 2007 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 "arm-linux-uclibcgnueabi"...
Using host libthread_db library "/lib/libthread_db.so.1".
(gdb) handle SIG32 nostop
Signal        Stop      Print   Pass to program Description
SIG32         No        Yes     Yes             Real-time event 32
(gdb) break sigwait
Breakpoint 1 at 0xe154
(gdb) cont
The program is not being run.
(gdb) run
Starting program: ...

Program received signal SIG32, Real-time event 32.

Program received signal SIG32, Real-time event 32.
Breakpoint 1 at 0x1a56bdfc
warning: Cannot initialize thread debugging library: generic error (~10
times)

Program received signal SIG32, Real-time event 32.  (~10 more times...)

[New LWP 350]
[New LWP 343]

<I hit ctrl-c (have to hit it twice for some reason)>

Program received signal SIGINT, Interrupt.
[Switching to LWP 343]
0x1a70daf0 in TimeUtils::addOffset (t=0x3e5ffc60, msecs=100)
    at ../../../../TimeUtils.h:68
68      ../../../../TimeUtils.h: No such file or directory.
        in ../../../../TimeUtils.h
(gdb) info threads
* 2 LWP 343  0x1a70daf0 in TimeUtils::addOffset (t=0x3e5ffc60,
msecs=100)
    at ../../jhcommon/include/TimeUtils.h:68
  1 LWP 350  0x1a82f44c in sigsuspend () from /lib/libc.so.0
(gdb) 


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