c-icap gets stuck while shutting down (reconfigure command then stop command)

[ae-ignatiev]

Hi
I have used c-icap for a long time and I have recently encountered a problem: c-icap got stuck while shutting down the process.
As I could figure out it happens in really rare conditions: there are two subsequent commands "reconfigure" and "stop" sent to command socket with small pause between them (I guess 0.3 - 0.5s):

      echo -n reconfigure > /var/run/c-icap/c-icap.ctl
      echo -n stop > /var/run/c-icap/c-icap.ctl

The reproducing is quite stable.

As I understand c-icap get stuck while it is waiting for child exit that have to be killed after reconfiguration command. Probably, the cause is in this condition in wait_childs_to_exit function (mpmt_server.c):

        if (q->childs[i].to_be_killed != IMMEDIATELY) {
            ci_debug_printf(5, "Child %d not signaled yet!\n", q->childs[i].pid);
            continue;
        }

to_be_killed here has GRACEFULLY value for those child processes.

Could you please take a look at this issue?
I understand that scenario is quite weird but it happened in my project. And I can't restart the whole service again due to this stuck (process still exists).

Processes/threads configuration in config-file:

StartServers 3
MaxServers 10
MinSpareThreads     10
MaxSpareThreads     10
ThreadsPerChild     10
MaxRequestsPerChild  1000

Version: 0.5.10
CentOS 7.9

Thank you!