The simple program below crashes recent 2.4 kernels. The network
stack appears to enter a busy loop; messages from the rate limiting
system are emitted to the console:
NET: XXXXX mesages suppressed
(but *no* other messages are printed).
Thomas.
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <errno.h>
int
main (int argc, char *argv[])
{
struct hostent *he;
int i = 1, s, fd;
struct sockaddr_in a;
fd_set rset, wset, eset;
unsigned char buf[16];
int len;
if ((he = gethostbyname ("localhost")) == NULL) {
perror ("gethostbyname");
exit (1);
}
s = socket (AF_INET, SOCK_STREAM, 0);
if (s < 0) { perror ("socket"); exit (1); }
setsockopt (s, SOL_SOCKET, SO_REUSEADDR, &i, sizeof i);
a.sin_family = PF_INET;
a.sin_port = 0;
a.sin_addr = *(struct in_addr *)(he->h_addr_list[0]);
bind (s, (struct sockaddr*) &a, sizeof a);
listen (s, 10);
len = sizeof a;
getsockname (s, (struct sockaddr *) &a, &len);
switch (fork()) {
case -1:
perror ("fork");
exit (1);
case 0: /* child: client */
puts ("@@10");
close (s);
s = socket (AF_INET, SOCK_STREAM, 0);
connect (s, (struct sockaddr*) &a, sizeof a);
puts ("@@11");
buf[0] = 1;
send (s, &buf, 1, MSG_OOB);
puts ("@@12");
sleep (2);
puts ("@@13");
buf[0] = 2;
send (s, &buf, 1, 0);
puts ("@@14");
return 0;
default: /* father: server */
puts ("@@00");
fd = accept (s, NULL, NULL);
FD_ZERO(&rset);
FD_ZERO(&wset);
FD_ZERO(&eset);
FD_SET (fd, &eset);
puts ("@@01");
select (fd + 1, &rset, &wset, &eset, NULL);
puts ("@@02");
len = recv (fd, &buf, sizeof buf, MSG_PEEK);
puts ("@@03");
if (len != 1 || buf[0] != 2)
{ perror ("recv"); exit (1); }
puts ("@@04");
while (1) {
if (wait (&i) == -1 && errno == ECHILD)
break;
}
return 0;
}
}
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