linux-kernel - unkillable process during core dump

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Message-ID: <20080506045811.GA23821@night.netis.ru>
Date:	Tue, 6 May 2008 08:58:11 +0400
From:	"Alexander V. Lukyanov" <lav@...is.ru>
To:	linux-kernel@...r.kernel.org
Subject: unkillable process during core dump

Hello!

I have noticed that a process doing a core dump is unkillable.
Now imagine that there are many such processes and they are large.
An example:

#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
int main() {
        calloc(1000000000,1);
        signal(SIGCLD,SIG_IGN);
        while(1) {
                if(fork()==0) {
                        raise(SIGABRT);
                        _exit(0);
                }
                sleep(10);
        }
        return 0;
}

Try with large enough ulimit -c and with sysctl kernel.core_uses_pid=0.
You kill the parent, but the children are still doing their core dumps.

-- 
   Alexander.
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