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Re: 2.4.14 prerelease call for testing #2

Hallvard B Furuseth wrote: 
With test050 and defined(HAVE_EPOLL), valgrind sometimes reports invalid
reads/writes in slapd_daemon_task().  Maybe that clobbers some memory
(like the garbage contextCSN mentioned previously).

Turning SLAP_EPOLL_SOCK_SET(s, mode) into a function shows that s == 9
but SLAP_EPOLL_SOCK_IX(s) == -1, so slap_daemon.sd_epolls[] gets a
negative index.

I don't know where to go from there.  Maybe hangup (below) doesn't
clean up after itself.

That's interesting. That would require receiving a Hangup event on a descriptor we've already removed from epoll's event list. How can that be? Have you seen this with CONNS debug messages enabled?

static void SLAP_EPOLL_SOCK_SET(int s, long mode) {
	long ix = SLAP_EPOLL_SOCK_IX(s);
	assert(ix>= 0);
	long ev = (slap_daemon.sd_epolls[ix]).events;
	if ( (ev&  (mode)) != (mode) ) {
		SLAP_EPOLL_SOCK_EV(s) |= (mode);
		epoll_ctl( slap_daemon.sd_epfd, EPOLL_CTL_MOD, (s),
			&SLAP_EPOLL_SOCK_EP(s) );
	}
}

(gdb) thread 3
[Switching to thread 3 (process 3915)]#3  0x0000000000419b9c in SLAP_EPOLL_SOCK_SET (s=9, mode=-2147483648) at daemon.c:181
181             assert(ix>= 0);
(gdb) backtrace
#0  0x000000350e230215 in raise () from /lib64/libc.so.6
#1  0x000000350e231cc0 in abort () from /lib64/libc.so.6
#2  0x000000350e229696 in __assert_fail () from /lib64/libc.so.6
#3  0x0000000000419b9c in SLAP_EPOLL_SOCK_SET (s=9, mode=-2147483648) at daemon.c:181
#4  0x000000000041ef40 in slapd_daemon_task (ptr=0x0) at daemon.c:2557
#5  0x000000350ee06367 in start_thread () from /lib64/libpthread.so.0
(gdb) frame 3
#3  0x0000000000419b9c in SLAP_EPOLL_SOCK_SET (s=9, mode=-2147483648) at daemon.c:181
181             assert(ix>= 0);

(gdb) print ix
$9 = -1
(gdb) print *slap_daemon.sd_index@128
$10 = {-1, -1, -1, -1, 0, -1, -1, 1, -1<repeats 120 times>}

(gdb) up
#4  0x000000000041ef40 in slapd_daemon_task (ptr=0x0) at daemon.c:2557
2557                                            SLAP_EPOLL_SOCK_SET( fd, EPOLLET );
(gdb) list
2552                                            Debug( LDAP_DEBUG_CONNS,
2553                                                    "daemon: hangup on %d\n", fd, 0, 0 );
2554    #ifdef HAVE_EPOLL
2555                                            /* Don't keep reporting the hangup
2556                                             */
2557                                            SLAP_EPOLL_SOCK_SET( fd, EPOLLET );
2558    #endif



--
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/