bash core dump in trap_handler

[Fergus Henderson]

Configuration Information [Automatically generated, do not change]:
Machine: i486
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i486' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i486-pc-linux-gnu' 
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL 
-DHAVE_CONFIG_H   -I.  -I../bash -I../bash/include -I../bash/lib   -g -O2
uname output: Linux digitopia.nyc.corp.google.com 2.6.18.5-gg10-mixed64-32 #1 
SMP Tue May 8 22:29:42 PDT 2007 x86_64 GNU/Linux
Machine Type: i486-pc-linux-gnu

Bash Version: 3.1
Patch Level: 17
Release Status: release

Description:
        Bash dumps core.

Repeat-By:
        Put the following commands in a script, and run it:
        
          #!/bin/bash
          trap 'trap "kill -2 $$" 0; trap - 2' 2
          pid=$$; { sleep 0.01; kill -2 $pid; } &
          sleep 0.02
        
        (This assumes you're using GNU sleep; if not, s/0.0//g and the bug will
        still exhibit itself, just a couple of seconds slower.)
        
        The resulting output from this script is
          trap_handler: bad signal 2
          Aborting...Aborted (core dumped)
        
        and examining the core gives the following stack trace
        
        (gdb) where
        #0  0xffffe410 in __kernel_vsyscall ()
        #1  0x463ad9a1 in raise () from /lib/tls/i686/cmov/libc.so.6
        #2  0x463af2b9 in abort () from /lib/tls/i686/cmov/libc.so.6
        #3  0x08075897 in programming_error ()
        #4  0x0808ac23 in trap_handler ()
        #5  <signal handler called>
        #6  0xffffe410 in __kernel_vsyscall ()
        #7  0x463addf6 in kill () from /lib/tls/i686/cmov/libc.so.6
        #8  0x08079756 in kill_pid ()
        #9  0x080a460b in kill_builtin ()
        #10 0x0806b3ac in dispose_exec_redirects ()
        #11 0x0806e810 in execute_shell_function ()
        #12 0x0806c96b in execute_command_internal ()
        #13 0x080a170d in parse_and_execute ()
        #14 0x0808a6b2 in run_exit_trap ()
        #15 0x0805becf in exit_shell ()
        #16 0x0805e34e in main ()