Re: get_printer_list_db: Failed to open printer_list.tdb

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On 08.03.2026 08:26, Michael Tokarev via samba wrote:
> Hi!
> 
> Sometimes, I'm seeing a lot of messages like this:
> 
> Mar 07 22:40:32 rpcd_spoolss[199894]: [2026/03/07 22:40:32.239192,  0] 
> source3/printing/printer_list.c:58(get_printer_list_db)
> Mar 07 22:40:32 rpcd_spoolss[199894]:   get_printer_list_db: Failed to 
> open printer_list.tdb
> Mar 07 23:40:46 rpcd_spoolss[200124]: [2026/03/07 23:40:46.123153,  0] 
> source3/printing/printer_list.c:58(get_printer_list_db)
> Mar 07 23:40:46 rpcd_spoolss[200124]:   get_printer_list_db: Failed to 
> open printer_list.tdb
> [global]
>          load printers = no
>          printing = BSD
>          printcap name = /dev/null
>          print command =  lpr -P%p -l -h -r %s
> 
> [hp1020]
>          printer = hp1020
>          comment = HP LaserJet 1020
>          printable = yes
>          path = /var/tmp
> 
> Samba version 4.23.5.

It has become worse.  The above messages are generated every 0.1s:

Apr 17 00:00:00 panda rpcd_spoolss[2186]: [2026/04/17 00:00:00.292537, 
0] source3/printing/printer_list.c:58(get_printer_list_db)
Apr 17 00:00:00 panda rpcd_spoolss[2186]:   get_printer_list_db: Failed 
to open printer_list.tdb
Apr 17 00:00:10 panda rpcd_spoolss[2186]: [2026/04/17 00:00:10.300551, 
0] source3/printing/printer_list.c:58(get_printer_list_db)
Apr 17 00:00:10 panda rpcd_spoolss[2186]:   get_printer_list_db: Failed 
to open printer_list.tdb
Apr 17 00:00:20 panda rpcd_spoolss[2186]: [2026/04/17 00:00:20.320819, 
0] source3/printing/printer_list.c:58(get_printer_list_db)
Apr 17 00:00:20 panda rpcd_spoolss[2186]:   get_printer_list_db: Failed 
to open printer_list.tdb
Apr 17 00:00:30 panda rpcd_spoolss[2186]: [2026/04/17 00:00:30.340662, 
0] source3/printing/printer_list.c:58(get_printer_list_db)
Apr 17 00:00:30 panda rpcd_spoolss[2186]:   get_printer_list_db: Failed 
to open printer_list.tdb
.. and so on, for whole day.

so I finally catched it.  Here's what's going on in strace:


...
epoll_create1(EPOLL_CLOEXEC)            = 16
writev(22, [{iov_base=",\0", iov_len=2}, 
{iov_base="\5\0\0\3\20\0\0\0,\0\0\0\37\0\0\0\24\0\0\0\0\0\5\0\1\0\0\0\3230\317\254"..., 
iov_len=44}], 2) = 46
epoll_ctl(16, EPOLL_CTL_ADD, 22, {events=EPOLLIN|EPOLLRDHUP, 
data=0x56442fad94a0}) = 0
epoll_wait(16, [{events=EPOLLIN, data=0x56442fad94a0}], 1, 10000) = 1
readv(22, [{iov_base="0\0", iov_len=2}], 1) = 2
readv(22, [{iov_base="\5\0\2\3\20\0\0\0000\0\0\0\37\0\0\0", iov_len=16}, 
{iov_base="\30\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 
iov_len=32}], 2) = 48
close(16)                               = 0
close(22)                               = 0
umask(000)                              = 000
mkdir("/run/samba", 0755)               = -1 EEXIST (File exists)
umask(000)                              = 000
newfstatat(AT_FDCWD, "/run/samba", {st_mode=S_IFDIR|0755, st_size=500, 
...}, AT_SYMLINK_NOFOLLOW) = 0
openat(AT_FDCWD, "/run/samba/printer_list.tdb", 
O_RDWR|O_CREAT|O_CLOEXEC, 0644) = -1 EACCES (Permission denied)
newfstatat(AT_FDCWD, "/etc/localtime", {st_mode=S_IFREG|0644, 
st_size=1535, ...}, 0) = 0
geteuid()                               = 1064
writev(3, [{iov_base="[2026/04/18 09:26:46.821290,  0]"..., iov_len=89}, 
{iov_base="  get_printer_list_db: Failed to"..., iov_len=66}], 2) = 155
getpid()                                = 40112
sendto(21, "<27>Apr 18 09:26:46 rpcd_spoolss"..., 130, MSG_NOSIGNAL, 
NULL, 0) = 130
getpid()                                = 40112
sendto(21, "<27>Apr 18 09:26:46 rpcd_spoolss"..., 107, MSG_NOSIGNAL, 
NULL, 0) = 107
fcntl(20, F_SETLKW, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=12124, 
l_len=1}) = 0
fcntl(20, F_SETLKW, {l_type=F_UNLCK, l_whence=SEEK_SET, l_start=12124, 
l_len=1}) = 0
fcntl(20, F_SETLKW, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=9868, 
l_len=1}) = 0
fcntl(20, F_SETLKW, {l_type=F_UNLCK, l_whence=SEEK_SET, l_start=9868, 
l_len=1}) = 0
fcntl(20, F_SETLKW, {l_type=F_WRLCK, l_whence=SEEK_SET, l_start=9868, 
l_len=1}) = 0
fcntl(20, F_SETLKW, {l_type=F_UNLCK, l_whence=SEEK_SET, l_start=9868, 
l_len=1}) = 0
openat(AT_FDCWD, "/run/samba/samba-bgqd.pid", O_RDONLY|O_NONBLOCK) = 16
read(16, "40117\n", 19)                 = 6
kill(40117, 0)                          = -1 EPERM (Operation not permitted)
fcntl(16, F_SETLK, {l_type=F_RDLCK, l_whence=SEEK_SET, l_start=0, 
l_len=1}) = -1 EAGAIN (Resource temporarily unavailable)
close(16)                               = 0
openat(AT_FDCWD, "/run/samba/msg.lock/40117", O_RDONLY|O_NONBLOCK) = 16
pread64(16, "10145467335826111398\n", 24, 0) = 21
close(16)                               = 0
socket(AF_UNIX, SOCK_DGRAM, 0)          = 16
connect(16, {sa_family=AF_UNIX, sun_path="/run/samba/msg.sock/40117"}, 
110) = -1 EACCES (Permission denied)
close(16)                               = 0
geteuid()                               = 1064
getegid()                               = 1064
getgroups(0, NULL)                      = 7
getgroups(7, [100, 1064, 3004, 5001, 5003, 5004, 5006]) = 7
geteuid()                               = 1064
...

This is rpcd_spoolss, running as a user (uid=1064), doing things as
user which aren't supposed to be run as user.

It looks like the whole thing here is quite broken.  It does many
strange things - like constantly poking /root/.krb5/config &
/etc/hx509.conf, constantly creating and destroying epool fd,
and some more.

But the most important is that it does the creation of a global
printer_list.db as user, not as root.

For now, in order to keep our systems a bit saner, I replaced
contents of get_printer_list_db() with "return NULL" - since
this file is never created anyway, and it has always been that
way, it looks like.  I wonder if I can do the same for debian,
to avoid having two builds (one local one debian), - and if yes,
maybe I can remove whole lot of other code which run this
function.

But this function should not be run as often (every 0.1s).

Thanks,

/mjt

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