Date: Fri, 29 Mar 2002 17:18:06 -0800 (PST) From: Gurusamy Sarathy <gsar@ActiveState.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/36515: SA_NOCLDWAIT has no effect when linking with -pthread Message-ID: <200203300118.g2U1I6W82724@freefall.freebsd.org>
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>Number: 36515
>Category: kern
>Synopsis: SA_NOCLDWAIT has no effect when linking with -pthread
>Confidential: no
>Severity: critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Mar 29 17:20:00 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: Gurusamy Sarathy
>Release: 4.2-RELEASE
>Organization:
ActiveState Corp.
>Environment:
FreeBSD clamp 4.2-RELEASE FreeBSD 4.2-RELEASE #0: Mon Nov 20 13:02:55 GMT 2000 jkh@bento.FreeBSD.org:/usr/src/sys/compile/GENERIC i386
>Description:
Merely linking a program with -pthread causes it to start producing
zombies, even though the program has explicitly set the SIGCHLD disposition using SA_NOCLDWAIT. Problem does not appear when not
linking with -pthread. The supplied test case should be self-
explanatory.
>How-To-Repeat:
/*
* Demonstrate that SA_NOCLDWAIT doesn't work when linking with -pthread
* under FreeBSD 4.2-RELEASE.
*
* This program has different behavior when built with and without
* -pthread. When built with -pthread, it will create zombies.
*
* The two variants can be built with:
*
* cc -o sig sig.c
* cc -o sig sig.c -pthread
*/
#include <stdio.h>
#include <signal.h>
#include <errno.h>
int
main(int ac, char **av)
{
struct sigaction sa;
sa.sa_handler = SIG_IGN;
sa.sa_flags = SA_NOCLDWAIT;
sigemptyset(&sa.sa_mask);
sigaction(SIGCHLD,&sa,NULL);
while (1) {
int c = fork();
if (c < 0) {
fprintf(stderr, "fork() failed: %s\n", strerror(errno));
exit(1);
}
if (!c) {
exit(0);
}
sleep(1);
}
}
>Fix:
Don't know of a fix, but the workaround is to install an explicit
handler to reap the children.
>Release-Note:
>Audit-Trail:
>Unformatted:
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