Description of problem:

If the backtrace is very deep it takes ages (up to a minute) to get a backtrace.

Version-Release number of selected component (if applicable):

gdb-7.1-30.fc13.i686

How reproducible:

Always.

Steps to Reproduce:

$ cat recurse.c
void bar ();

void foo ()
{
  bar ();
}

void bar ()
{
  foo ();
}

int main (int argc, char **argv)
{
  foo();
  return 0;
}
$ gcc -g -o recurse recurse.c
$ gdb ./recurse
GNU gdb (GDB) Fedora (7.1-30.fc13)
Copyright (C) 2010 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 "i686-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/mark/src/tests/recurse...done.
(gdb) run
Starting program: /home/mark/src/tests/recurse 

Program received signal SIGSEGV, Segmentation fault.
bar () at recurse.c:10
10	  foo ();
(gdb) bt
<wait a long time, wonder if gdb froze...>
<finally...>
#0  bar () at recurse.c:10
#1  0x0804839f in foo () at recurse.c:5
#2  0x080483ac in bar () at recurse.c:10
#3  0x0804839f in foo () at recurse.c:5
#4  0x080483ac in bar () at recurse.c:10
#5  0x0804839f in foo () at recurse.c:5
#6  0x080483ac in bar () at recurse.c:10
#7  0x0804839f in foo () at recurse.c:5
#8  0x080483ac in bar () at recurse.c:10
#9  0x0804839f in foo () at recurse.c:5
#10 0x080483ac in bar () at recurse.c:10
<etc.>
---Type <return> to continue, or q <return> to quit---
  
Actual results:

Long delay before showing (first part) of backtrace.

Expected results:

Showing (first part) of backtrace immediately.

Additional info:

If gdb is paginated anyway, don't try to do a full backtrace at once.
Just lookup the top couple of frames (at most as many as lines in one
pager page). This would not just speedup backtraces in dumb situations
like mine. But I am often not really interested in the frames beyond the
first page anyway.