Strange select(2) misbehaviour when linked with -pthread

[Maxim Sobolev]

Hi,

I found that the attached small program behaves very strangely when
linked with -pthread - it chews 100% CPU cycles while waiting in
select(2). This misbehaviour observed both on 5-CURRENT and 4-STABLE
systems. *weird*

-Maxim
P.S. And yes, I know that I ought to use NULL instead of &tv when I
want to wait indefinitely in select(2), but it is how some programs
work.

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>

int main()
{
        int retval, fd;
        u_int32_t timeout;
        struct timeval tv;
        fd_set mask;

        fd = 0;
        timeout = ~0;
        tv.tv_sec = timeout/1000;
        tv.tv_usec = (timeout%1000)*1000;
        FD_ZERO(&mask);
        FD_SET(fd, &mask);

        retval = select(1, &mask, NULL, NULL, &tv);
        exit(0);
}