lockup in bgp_delete()

[Luke Shumaker]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-unknown-linux-gnu' 
-DCONF_VENDOR='unknown' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' 
-DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib  -D_FORTIFY_SOURCE=2 
-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong 
-DDEFAULT_PATH_VALUE='/usr/local/sbin:/usr/local/bin:/usr/bin' 
-DSTANDARD_UTILS_PATH='/usr/bin' -DSYS_BASHRC='/etc/bash.bashrc' 
-DSYS_BASH_LOGOUT='/etc/bash.bash_logout' -DNON_INTERACTIVE_LOGIN_SHELLS 
-Wno-parentheses -Wno-format-security
uname output: Linux build64-par 4.9.11-gnu-1 #1 SMP PREEMPT Sun Feb 19 18:36:28 
UYT 2017 x86_64 GNU/Linux
Machine Type: x86_64-unknown-linux-gnu

Bash Version: 4.4
Patch Level: 12
Release Status: release

Description:

        Occasionally, on one of my servers, a bash script in a cron
        job locks up, and pegs one of the CPU cores at 100%.
        Attaching to it with GDB, I see that it is stuck in the loop
        in bgp_delete; it is looking for the index of the pid to
        delete in bgpids.storage, but it's not there.  And
        bgpids.storage being a circular linked list, it just loops
        around and around, never exiting the loop.

Repeat-By:

        I'm not sure.  I've seen it 3 times: on 2017-02-18 (with
        4.4.11), 2017-02-27 (with 4.4.11), and 2017-03-20 (with
        4.4.12).  The cron job runs daily.  So I don't quite know what
        causes it.  I've left it running, and can attach to it with
        GDB to answer questions, or anything.

-- 
Happy hacking,
~ Luke Shumaker