Trouble with GDB and specific app on 7.0-CURRENT....

From: Eric Schuele <e.schuele_at_computer.org>
Date: Thu, 27 Sep 2007 23:18:01 -0500
Hello,

I have a particular app that I am unable to debug using gdb.  When I
attach to the app and continue it, gdb begins to take up 100% of my cpu.
 It will do this forever (well longer than I've ever waited).

I am able to debug this particular app on my 6.2-STABLE machine.  And I
can debug other apps on my 7.0 machine.  I've tried both gdb 6.1 and gdb
6.6 on my 7.0 machine with no change in behavior.

I first thought maybe I had done something odd when rebuilding my
kernel/world?  But I've built a second 7.0 machine and stuck with the
GENERIC kernel and I have the same results.

Most times I can not break into the app once I have continued it.  I
have attached gdb to gdb to watch what it is doing and it appears to
give me a few different backtraces, though it is always one of maybe
three traces.  [See below for bt of gdb attached to gdb, unfortunately
its not the same bt I was seeing... but may offer some insight?]

Has anyone seen behavior like this?  What else can I provide that might
help diagnose this?

-- 
Regards,
Eric

Backtrace of gdb ==> gdb
#0  0x2874cbbb in ptrace () from /lib/libc.so.7
#1  0x08068b42 in i386fbsd_resume (ptid={pid = -1, lwp = 0, tid = 0},
step=0,
    signal=TARGET_SIGNAL_CHLD) at i386fbsd-nat.c:76
#2  0x080ed0de in resume (step=0, sig=TARGET_SIGNAL_CHLD) at infrun.c:626
#3  0x080f05ed in keep_going (ecs=0xbfbfe544) at infrun.c:2892
#4  0x080ef284 in handle_inferior_event (ecs=0xbfbfe544) at infrun.c:2021
#5  0x080ed63e in wait_for_inferior () at infrun.c:1009
#6  0x080ed46a in proceed (addr=4294967295, siggnal=TARGET_SIGNAL_DEFAULT,
    step=0) at infrun.c:827
#7  0x080ea249 in continue_command (proc_count_exp=0x0, from_tty=1)
    at infcmd.c:642
#8  0x0808082b in do_cfunc (c=0x28977190, args=0x0, from_tty=1)
    at .././gdb/cli/cli-decode.c:62
#9  0x08082e6d in cmd_func (cmd=0x28977190, args=0x0, from_tty=1)
    at .././gdb/cli/cli-decode.c:1666
#10 0x08054cbd in execute_command (p=0x2890c081 "", from_tty=1) at top.c:455
#11 0x080feadf in command_handler (command=0x2890c080 "c") at
event-top.c:519
#12 0x080ff307 in command_line_handler (rl=0x2895b112 "c") at
event-top.c:804
#13 0x28319826 in rl_callback_read_char () from /lib/libreadline.so.7
#14 0x080fe1cf in rl_callback_read_char_wrapper (client_data=0x0)
    at event-top.c:179


Received on Fri Sep 28 2007 - 02:18:03 UTC

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