winbind assertation failed (samba 3.0.32): both EVENT_FD_WRITE and EVENT_FD_READ are set for event

Volodymyr Khomenko Volodymyr.Khomenko at
Fri Nov 21 13:26:48 GMT 2008

Hi all,

I've encountered pity issue with winbindd for samba 3.0.32:
it claimed about 'asseration failed' inside nsswitch/winbindd.c:rw_callback. Corrsponding code looks like this:

static void rw_callback(struct fd_event *event, int flags)
    if (event->flags & EVENT_FD_WRITE) {
        SMB_ASSERT(flags == EVENT_FD_WRITE);
    if (event->flags & EVENT_FD_READ) {
        SMB_ASSERT(flags == EVENT_FD_READ);

I've checked this by gdb and received:
#5  0x00da573b in rw_callback (event=0x9464f3c, flags=3) at nsswitch/winbindd.c:415
#6  0x00da6ae3 in process_loop () at nsswitch/winbindd.c:924
#7  0x00da7514 in main (argc=5, argv=0xbffc3414, envp=0xbffc342c) at nsswitch/winbindd.c:1195

I see that flags=3 (both EVENT_FD_WRITE=2 and EVENT_FD_READ=1 are set by process_loop):

    ev = fd_events;
    while (ev != NULL) {
        int flags = 0;
        if (FD_ISSET(ev->fd, &r_fds))
            flags |= EVENT_FD_READ;
        if (FD_ISSET(ev->fd, &w_fds))
            flags |= EVENT_FD_WRITE;
        if (flags)
            ev->handler(ev, flags);

So what's wrong with such flags? Why do we suppose that only READ or WRITE flag has to be set?
Shouln'd we fix SMB_ASSERT statements to allow both flags?

Thanks for help,
Volodymyr Khomenko
Software Engineer - Core Technologies, Exanet Ltd.

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