[Samba] Slow reply to "smbclient -NL localhost" : strace

[Gilles]

On 05/11/2024 11:12, Rowland Penny via samba wrote:
> I took a look at your strace again and I noticed that the hostname was
> 'sheevaplug', now I can only really think of one reason why such a
> hostname would be used, if it was an actual Sheevaplug.
>
> If this is a Sheevaplug, then that could be your problem.
>  From memory, the Sheevaplug had a single core ARM CPU, running at just
> over 1GHZ with about 512MB of memory. To be honest I haven't heard of
> one of these for years, they were supplanted by the Raspberry pi, a
> much more capable computer, that has only got better and better.

I've used it for years on a home network, and it worked fine with Debian 
11. That problem only appeared after I installed Debian 12 (Linux 
6.1.0-26-marvell #1 Debian 6.1.112-1 (2024-09-30) armv5tel GNU/Linux).

"strace -r smbclient -NL localhost" shows the two locations where it's 
hanging when listing the shares:
=================
…
0.000410 statx(1, "", 
AT_STATX_SYNC_AS_STAT|AT_NO_AUTOMOUNT|AT_EMPTY_PATH, STATX_BASIC_STATS, 
{stx_mask=STATX_BASIC_STATS|STATX_MNT_ID, stx_attributes=0, 
stx_mode=S_IFCHR|0600, stx_size=0, ...}) = 0
0.001078 write(1, "\n", 1
)         = 1
0.000987 write(1, "\tSharename       Type      Comme"..., 35 
Sharename       Type      Comment
) = 35
0.000883 write(1, "\t---------       ----      -----"..., 35 
---------       ----      -------
) = 35
0.000466 epoll_create(64)          = 3
0.000873 fcntl64(3, F_GETFD)       = 0
0.000318 fcntl64(3, F_SETFD, FD_CLOEXEC) = 0
0.000890 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806466, 
tv_nsec=500839090}) = 0
0.000555 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806466, 
tv_nsec=501842685}) = 0
0.000997 epoll_ctl(3, EPOLL_CTL_ADD, 5, 
{events=EPOLLIN|EPOLLERR|EPOLLHUP, data={u32=37735016, u64=37735016}}) = 0
0.000889 writev(5, [{iov_base="\0\0\0\204", iov_len=4}, 
{iov_base="\376SMB@\0\1\0\0\0\0\0\5\0\1\0\20\0\0\0\0\0\0\0\4\0\0\0\0\0\0\0"..., 
iov_len=64}, 
{iov_base="9\0\0\0\2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\237\1\2\0\0\0\0\0"..., 
iov_len=56}, {iov_base="s\0r\0v\0s\0v\0c\0", iov_len=12}], 4) = 136
0.005154 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806466, 
tv_nsec=508444761}) = 0
0.003823 epoll_wait(3, [{events=EPOLLIN, data={u32=37735016, 
u64=37735016}}], 1, 19994) = 1
*8.784598 recv(5, "\0\0\0\230", 4, 0) = 4*
0.000404 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806475, 
tv_nsec=297225024}) = 0
0.000858 epoll_wait(3, [{events=EPOLLIN, data={u32=37735016, 
u64=37735016}}], 1, 11205) = 1
0.000439 recv(5, 
"\376SMB@\0\1\0\0\0\0\0\5\0\1\0\21\0\0\0\0\0\0\0\4\0\0\0\0\0\0\0"..., 
152, 0) = 152
0.000957 epoll_ctl(3, EPOLL_CTL_DEL, 5, 0xbe9be018) = 0
0.001919 close(3)                  = 0
…
0.001138 epoll_create(64)          = 3
0.000808 fcntl64(3, F_GETFD)       = 0
0.000322 fcntl64(3, F_SETFD, FD_CLOEXEC) = 0
0.000927 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806475, 
tv_nsec=319588164}) = 0
0.000646 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806475, 
tv_nsec=320668191}) = 0
0.000908 epoll_ctl(3, EPOLL_CTL_ADD, 5, 
{events=EPOLLIN|EPOLLERR|EPOLLHUP, data={u32=37743504, u64=37743504}}) = 0
0.000876 writev(5, [{iov_base="\0\0\0\300", iov_len=4}, 
{iov_base="\376SMB@\0\1\0\0\0\0\0\v\0\1\0\20\0\0\0\0\0\0\0\5\0\0\0\0\0\0\0"..., 
iov_len=64}, 
{iov_base="9\0\0\0\27\300\21\0\234\366\306j\0\0\0\0%\22\204\252\0\0\0\0x\0\0\0H\0\0\0"..., 
iov_len=56}, 
{iov_base="\5\0\v\3\20\0\0\0H\0\0\0\1\0\0\0\270\20\270\20\0\0\0\0\1\0\0\0\0\0\1\0"..., 
iov_len=72}], 4) = 196
0.006494 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806475, 
tv_nsec=328507149}) = 0
0.001085 epoll_wait(3, [{events=EPOLLIN, data={u32=37743504, 
u64=37743504}}], 1, 9992) = 1
0.002549 recv(5, "\0\0\0I", 4, 0)  = 4
0.000514 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806475, 
tv_nsec=333154493}) = 0
0.001046 epoll_wait(3, [{events=EPOLLIN, data={u32=37743504, 
u64=37743504}}], 1, 9987) = 1
0.007375 recv(5, 
"\376SMB@\0\0\0\3\1\0\0\v\0\1\0\23\0\0\0\0\0\0\0\5\0\0\0\0\0\0\0"..., 
73, 0) = 73
0.001112 epoll_ctl(3, EPOLL_CTL_DEL, 5, 0xbe9be018) = 0
0.000467 epoll_ctl(3, EPOLL_CTL_ADD, 5, 
{events=EPOLLIN|EPOLLERR|EPOLLHUP, data={u32=37745048, u64=37745048}}) = 0
0.000919 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806475, 
tv_nsec=343563494}) = 0
0.000966 epoll_wait(3, [{events=EPOLLIN, data={u32=37745048, 
u64=37745048}}], 1, 9977) = 1
*2.461278 recv(5, "\0\0\0\264", 4, 0) = 4*
0.000409 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806477, 
tv_nsec=806182845}) = 0
0.000832 epoll_wait(3, [{events=EPOLLIN, data={u32=37745048, 
u64=37745048}}], 1, 7514) = 1
0.000438 recv(5, 
"\376SMB@\0\1\0\0\0\0\0\v\0\0\0\23\0\0\0\0\0\0\0\5\0\0\0\0\0\0\0"..., 
180, 0) = 180
0.004769 epoll_ctl(3, EPOLL_CTL_DEL, 5, 0xbe9be018) = 0
0.000697 clock_gettime64(CLOCK_REALTIME, {tv_sec=1730806477, 
tv_nsec=812966277}) = 0
0.001364 close(3)                  = 0
…
=================