Re: crash in pipe_create()

[Matthias Drochner <M.Drochner%fz-juelich.de@localhost>]

While we are here: As reported by Scott Ellis and Tobias Nygren
on current-users, some "configure" test crashes the system.
I've just looked at it and found that the appended little
program triggers the crash if started 2 times in succession.
It happens in knote() traversing the list of knotes,
due to an invalid kn_selnext link.
There are some "XXXAD" comments in kern_event.c which
suggest that you might already know the problem...

best regards
Matthias





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Dr. Sebastian M. Schmidt
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#include <sys/types.h>
#include <sys/time.h>
#include <sys/event.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>

int
main(int argc, char **argv)
{
        int kq;
        int n;
        int fd[2];
        struct kevent ev;
#if 0
        struct timespec ts;
#endif
        char buf[8000];

        if (pipe(fd) == -1)
                exit(1);
        if (fcntl(fd[1], F_SETFL, O_NONBLOCK) == -1)
                exit(1);

        while ((n = write(fd[1], buf, sizeof(buf))) == sizeof(buf))
                ;

        if ((kq = kqueue()) == -1)
                exit(1);

        ev.ident = fd[1];
        ev.filter = EVFILT_WRITE;
        ev.flags = EV_ADD | EV_ENABLE;
        n = kevent(kq, &ev, 1, NULL, 0, NULL);
        if (n == -1)
                exit(1);

        read(fd[0], buf, sizeof(buf));

#if 0
        ts.tv_sec = 0;
        ts.tv_nsec = 0;
        n = kevent(kq, NULL, 0, &ev, 1, &ts);
        if (n == -1 || n == 0)
                exit(1);
#endif

        exit(0);
}