>Number:         26567
>Category:       kern
>Synopsis:       closef deadlock with threads
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Aug 06 06:44:00 UTC 2004
>Closed-Date:
>Last-Modified:
>Originator:     YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
>Release:        NetBSD 2.0G
>Organization:

>Environment:
	
	
System: NetBSD kaeru 2.0G NetBSD 2.0G (build.kaeru) #1594: Thu Aug 5 06:34:13 JST 2004 takashi@kaeru:/home/takashi/work/kernel/build.kaeru i386
Architecture: i386
Machine: i386
>Description:
	our descriptor handling code has an assumption that
	a file is kept in a descriptor table during the most operations.
	however, it no longer be held these days due to pthread and clone(2).

>How-To-Repeat:
	run the following test code and see that
	the main thread blocks at the first close(2) while
	the test() thread blocks in read(2) forever.

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int fds[2];

void *
test(void *dummy)
{
	char buf[1];
	int rv;

	rv = read(fds[0], buf, 1);		/* WILL BLOCK HERE */
	if (rv == 0) {
		fprintf(stderr, "EOF\n");
	} else if (rv == -1) {
		perror("read");
		exit(1);
	} else {
		fprintf(stderr, "%d\n", rv);
		exit(1);
	}

	return NULL;
}

int
main()
{
	pthread_t t;

	if (pipe(fds)) {
		perror("pipe");
		exit(1);
	}
	if (pthread_create(&t, NULL, test, NULL)) {
		perror("create");
		exit(1);
	}
	fprintf(stderr, "sleep\n");
	sleep(1);
	fprintf(stderr, "close\n");
	if (close(fds[0])) {			/* WILL BLOCK HERE */
		perror("close");
		exit(1);
	}
	fprintf(stderr, "close writer\n");
	if (close(fds[1])) {
		perror("close");
		exit(1);
	}
	fprintf(stderr, "join\n");
	if (pthread_join(t, NULL)) {
		perror("join");
		exit(1);
	}
	exit(0);
}

>Fix:
	unify f_count and f_usecount?

>Release-Note:
>Audit-Trail:
>Unformatted: