smbstatus getting a SIGBUS error

[Arnold Troeger]

Somemore information regarding the smbstatus error.

The sigbus error is occuring where I noted below.  I now have data
values to go along with the location.  The SIGBUS generating bit is
"entry_scanner_p->e.pid" which looks to be in an unaccessable area of
memory.  Looking back through the code, I find a couple of bizarities. 
For example file_scanner_p->num_share_mode_entries comes back as
1651272501, which, if I understand the code, is a bit large.  It looks
as if the code is accessing memory it's not supposed to be accessing. 
Well, it looks like a memory error.  I'd been meaning to try out the new
version of Purify anyway, so I guess I'll go ahead and download it. 
Feel free to jump in with comments or questions

Best regards
Arnold

Here's the offending routine:

/*******************************************************************
call the specified function on each entry under management by the
share mode system
********************************************************************/
static int shm_share_forall(void (*fn)(share_mode_entry *, char *))
{
        int i, count=0;
        int *mode_array;
        share_mode_record *file_scanner_p;
        shm_share_mode_entry *entry_scanner_p;

        mode_array = (int
*)shmops->offset2addr(shmops->get_userdef_off());

        for( i = 0; i < shmops->hash_size(); i++) {
                shmops->lock_hash_entry(i);
                if(mode_array[i] == 0)  {
                        shmops->unlock_hash_entry(i);
                        continue;
                }

                file_scanner_p = (share_mode_record
*)shmops->offset2addr(mode_array[i]);
                while((file_scanner_p != 0) && 
                      (file_scanner_p->num_share_mode_entries != 0)) {
                        shm_share_mode_entry *entry_scanner_p = 
                                (shm_share_mode_entry *)
                               
shmops->offset2addr(file_scanner_p->share_mode_entries);

                        while(entry_scanner_p != 0) {
                                
                                if
(process_exists(entry_scanner_p->e.pid)) {
                                        fn(&entry_scanner_p->e, 
                                           file_scanner_p->file_name);
                                        count++;
                                }

                                entry_scanner_p = 
                                        (shm_share_mode_entry *)
                                        shmops->offset2addr(
                                                           
entry_scanner_p->next_share_mode_entry);
                        } /* end while entry_scanner_p */
                        file_scanner_p = (share_mode_record *)
                               
shmops->offset2addr(file_scanner_p->next_offset)
;
                } /* end while file_scanner_p */
                shmops->unlock_hash_entry(i);
        } /* end for */

        return count;
}






-------- Original Message --------
Subject: smbstatus getting a SIGBUS error
Date: Thu, 08 Jun 2000 13:52:13 +0700
From: Arnold Troeger <stssart at bkk.unocal.com>
To: samba-bugs at samba.org
CC: arnold.troeger at bkk.unocal.com

I'm running Samba 2.0.7 and have been having a few problems with it.
Just to keep things focused, I'll stick with smbstatus as this one has
been the longest lasting problem.  The problem:  smbstatus functions
normally for some small bit of time after the samba daemons are
started.  At some point after a significant number of users have
connected to the Samba server, smbstatus starts crashing with a bus
error.  In this state, it will report on the connections but fails when
looking at the locks.  I had a go at running gdb on the program and have
located the point of failure in "locking_shm.c" in the
"shm_share_forall"
routine: line 636

(gdb) s
shm_offset2addr (offset=1096040751) at ../locking/shmem_sysv.c:154
154        if (offset == 0 )
(gdb) s
157        if (!shm_header_p)
(gdb) s
160        return (void *)((char *)shm_header_p + offset);
(gdb) s
161     }
(gdb) s
shm_share_forall (fn=0x136b4 <print_share_mode>)
    at ../locking/locking_shm.c:634
634                             while(entry_scanner_p != 0) {
(gdb) s
636                                     if
(process_exists(entry_scanner_p->e.pid)) {
(gdb) s

Program received signal SIGBUS, Bus error.
0x17b88 in shm_share_forall (fn=0x136b4 <print_share_mode>)
    at ../locking/locking_shm.c:636
636                                     if
(process_exists(entry_scanner_p->e.pid)) {
(gdb)

My Samba server is an E4000 with 6 CPUs running Solaris 2.6 and set up
with 1.3 TeraBytes of disk.

Thanks in advance for your assistance.

Best regards,
Arnold