fcntl spinlock in Linux?

[Alex Korobkin]

Found it, seems to work for Ubuntu server as well.

So, idle processes are doing this:
#0  0x00007ffd3141e2d8 in poll () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007ffd347abed0 in sys_poll ()
#2  0x00007ffd3452cba1 in smbd_process ()
#3  0x00007ffd34a3841f in ?? ()
#4  0x00007ffd347dcb0e in run_events_poll ()
#5  0x00007ffd347dccaa in ?? ()
#6  0x00007ffd34a396c0 in _tevent_loop_once ()
#7  0x00007ffd344aa456 in main ()

Non-idle ones are doing this:
#0  0x00007f97eb732e05 in fcntl () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007f97ebe35032 in ?? () from /usr/lib/x86_64-linux-gnu/libtdb.so.1
#2  0x00007f97ebe354fa in ?? () from /usr/lib/x86_64-linux-gnu/libtdb.so.1
#3  0x00007f97ebe349ed in tdb_traverse () from
/usr/lib/x86_64-linux-gnu/libtdb.so.1
#4  0x00007f97eeacddf6 in ?? ()
#5  0x00007f97eeab73ba in ?? ()
#6  0x00007f97eeab7f84 in printer_list_run_fn ()
#7  0x00007f97eeaaeac9 in pcap_printer_fn ()
#8  0x00007f97eeab4a56 in load_printers ()
#9  0x00007f97ee7cedfb in reload_printers ()
#10 0x00007f97eeac5be9 in messaging_dispatch_rec ()
#11 0x00007f97eeac74d1 in ?? ()
#12 0x00007f97eed50f1a in tevent_common_check_signal ()
#13 0x00007f97eeaf27e5 in run_events_poll ()
#14 0x00007f97ee842b8c in smbd_process ()
#15 0x00007f97eed4e41f in ?? ()
#16 0x00007f97eeaf2b0e in run_events_poll ()
#17 0x00007f97eeaf2caa in ?? ()
#18 0x00007f97eed4f6c0 in _tevent_loop_once ()
#19 0x00007f97ee7c0456 in main ()

I'm attaching gstack output for the reference.
Is it getting stuck when reloading list of printers?




2013/8/17 Volker Lendecke <Volker.Lendecke at sernet.de>

> On Fri, Aug 16, 2013 at 05:46:38PM -0400, Alex Korobkin wrote:
> > Here is a similar dump from a printserver running with ~50 smbd
> processes.
> > Samba 3.6.18, libtdb 1.2.12, Ubuntu 12.04 x64. Is this what you wanted to
> > have a look at?
>
> No, that's not what I had in mind. Fedora/RHEL have a
> utility called gstack that prints a user-space stack using
> the gdb "bt" subcommand. That is what I need. Maybe Fedora
> people can point you at the source for that utility, it's
> essentially a shell script wrapper around gdb. Very handy :-)
>
> Volker
>
> --
> SerNet GmbH, Bahnhofsallee 1b, 37081 Göttingen
> phone: +49-551-370000-0, fax: +49-551-370000-9
> AG Göttingen, HRB 2816, GF: Dr. Johannes Loxen
> http://www.sernet.de, mailto:kontakt at sernet.de
>
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