[Samba] Samba daemons hang trying to lock locking.tdb

[Fermin Molina]

Hi,

A day or so after starting samba, some daemons (diferent forks) begin to
hang. Then, the WinXP clients hang too completely.

When I try to figure out what is happen, I see that smbd daemons hangs
always in a fcntl64() call:

# strace -p 6414
Process 6414 attached - interrupt to quit
fcntl64(14, F_SETLKW64, {type=F_WRLCK, whence=SEEK_SET, start=3684, len=1}  <unfinished ...>
Process 6414 detached
# 

The file descriptor 14 corresponds to /var/lib/samba/locking.tdb file.
A backtrace using gdb from one stalled daemon:

(gdb) bt
#0  0x00faf402 in __kernel_vsyscall ()
#1  0x003dbd7a in fcntl () from /lib/libc.so.6
#2  0x008e50eb in tdb_set_lock_alarm () from /usr/sbin/smbd
#3  0x008e5307 in tdb_set_lock_alarm () from /usr/sbin/smbd
#4  0x008e5868 in tdb_chainlock () from /usr/sbin/smbd
#5  0x00880da8 in get_share_mode_lock () from /usr/sbin/smbd
#6  0x00881677 in get_delete_on_close_flag () from /usr/sbin/smbd
#7  0x007718fb in reply_trans2 () from /usr/sbin/smbd
#8  0x007906bc in smb_fn_name () from /usr/sbin/smbd
#9  0x007913c4 in process_smb () from /usr/sbin/smbd
#10 0x00791899 in smbd_process () from /usr/sbin/smbd
#11 0x0096c5c0 in main () from /usr/sbin/smbd
(gdb)


A backtrace from another stalled daemon:


(gdb) bt
#0  0x00faf402 in __kernel_vsyscall ()
#1  0x003dbd7a in fcntl () from /lib/libc.so.6
#2  0x008e50eb in tdb_set_lock_alarm () from /usr/sbin/smbd
#3  0x008e5307 in tdb_set_lock_alarm () from /usr/sbin/smbd
#4  0x008e5868 in tdb_chainlock () from /usr/sbin/smbd
#5  0x00880da8 in get_share_mode_lock () from /usr/sbin/smbd
#6  0x0077ab8b in open_file_ntcreate () from /usr/sbin/smbd
#7  0x0074a922 in reply_ntcreate_and_X () from /usr/sbin/smbd
#8  0x007906bc in smb_fn_name () from /usr/sbin/smbd
#9  0x007913c4 in process_smb () from /usr/sbin/smbd
#10 0x00791899 in smbd_process () from /usr/sbin/smbd
#11 0x0096c5c0 in main () from /usr/sbin/smbd
(gdb)       


The number of smbd daemons stalled increases in time.
I'm using FC4 with last updates installed and samba 3.0.21a.

Maybe is a kernel related problem with file locking?

Thanx in advance!

-- 
Fermin Molina Ibarz
Tècnic sistemes - ASIC
Universitat de Lleida
Tel: +34 973 702151
GPG: 0x060F857A