bug#20816: Excessive negative cache time for DNS lookups

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* bug#20816: Excessive negative cache time for DNS lookups
@ 2015-06-15  2:43 Mark H Weaver
  2015-06-15 13:15 ` Thompson, David
  2015-06-15 20:02 ` Ludovic Courtès
  0 siblings, 2 replies; 3+ messages in thread
From: Mark H Weaver @ 2015-06-15  2:43 UTC (permalink / raw)
  To: 20816

On my GuixSD system, DNS lookup failures (due to lack of network) are
cached for at least 4 minutes, and possibly much longer (I've not had
the patience to wait until it expires).

Even after restarting nscd, the negative cache entry persists for about
another 20 seconds.

I run into this problem quite frequently after waking my system up from
suspend-to-ram.  It typically takes several seconds for wicd to
establish a network connection, and if I make the mistake of triggering
a name lookup of my server (world.peace.net), then I must do the
following:

(1) deco restart nscd
(2) wait about 20 seconds

Looking at %nscd-default-caches in (gnu services base), I see that the
intent is to cache host lookup failures for 20 seconds, and service
lookup failures for an hour.  The fact that the negative cache entry
persists for 20 seconds after restarting nscd would seem to indicate
that nscd considers this to be a host lookup.  So perhaps this is a bug
in nscd.

Is anyone else able to reproduce this problem?

      Mark

^ permalink raw reply	[flat|nested] 3+ messages in thread

* bug#20816: Excessive negative cache time for DNS lookups
  2015-06-15  2:43 bug#20816: Excessive negative cache time for DNS lookups Mark H Weaver
@ 2015-06-15 13:15 ` Thompson, David
  2015-06-15 20:02 ` Ludovic Courtès
  1 sibling, 0 replies; 3+ messages in thread
From: Thompson, David @ 2015-06-15 13:15 UTC (permalink / raw)
  To: Mark H Weaver; +Cc: 20816

On Sun, Jun 14, 2015 at 10:43 PM, Mark H Weaver <mhw@netris.org> wrote:
> On my GuixSD system, DNS lookup failures (due to lack of network) are
> cached for at least 4 minutes, and possibly much longer (I've not had
> the patience to wait until it expires).
>
> Even after restarting nscd, the negative cache entry persists for about
> another 20 seconds.
>
> I run into this problem quite frequently after waking my system up from
> suspend-to-ram.  It typically takes several seconds for wicd to
> establish a network connection, and if I make the mistake of triggering
> a name lookup of my server (world.peace.net), then I must do the
> following:
>
> (1) deco restart nscd
> (2) wait about 20 seconds
>
> Looking at %nscd-default-caches in (gnu services base), I see that the
> intent is to cache host lookup failures for 20 seconds, and service
> lookup failures for an hour.  The fact that the negative cache entry
> persists for 20 seconds after restarting nscd would seem to indicate
> that nscd considers this to be a host lookup.  So perhaps this is a bug
> in nscd.
>
> Is anyone else able to reproduce this problem?

Yes, I had this exact same issue on Friday after having wireless
network connectivity problems.

- Dave

^ permalink raw reply	[flat|nested] 3+ messages in thread

* bug#20816: Excessive negative cache time for DNS lookups
  2015-06-15  2:43 bug#20816: Excessive negative cache time for DNS lookups Mark H Weaver
  2015-06-15 13:15 ` Thompson, David
@ 2015-06-15 20:02 ` Ludovic Courtès
  1 sibling, 0 replies; 3+ messages in thread
From: Ludovic Courtès @ 2015-06-15 20:02 UTC (permalink / raw)
  To: Mark H Weaver; +Cc: 20816

[-- Attachment #1: Type: text/plain, Size: 3735 bytes --]

Mark H Weaver <mhw@netris.org> skribis:

> On my GuixSD system, DNS lookup failures (due to lack of network) are
> cached for at least 4 minutes, and possibly much longer (I've not had
> the patience to wait until it expires).
>
> Even after restarting nscd, the negative cache entry persists for about
> another 20 seconds.

To reproduce it, I ran ‘guix system vm’ on this:

--8<---------------cut here---------------start------------->8---
(use-modules (gnu) (guix))
(use-package-modules base)

(operating-system
  (host-name "komputilo")
  (timezone "Europe/Berlin")
  (locale "en_US.UTF-8")
  (bootloader (grub-configuration (device "/dev/sdX")))
  (file-systems (cons (file-system
                        (device "root")
                        (title 'label)
                        (mount-point "/")
                        (type "ext4"))
                      %base-file-systems))
  (packages (cons* (canonical-package glibc) %base-packages))
  (services (map (lambda (mservice)
                   (mlet %store-monad ((service mservice))
                     (if (memq 'nscd (service-provision service))
                         (nscd-service (nscd-configuration
                                        (debug-level 10)))
                         mservice)))
                 %base-services)))
--8<---------------cut here---------------end--------------->8---

Then I had one console running “tail -f /var/log/nscd.log”, and another
one where I would run “ping www.gnu.org.”

Initially looking up www.gnu.org fails (because the network is down),
and nscd.log indeed shows:

--8<---------------cut here---------------start------------->8---
Mon Jun 15 21:04:20 2015 - 276: handle_request: request received (Version = 2) from PID 296
Mon Jun 15 21:04:20 2015 - 276: 	GETAI (www.gnu.org)
Mon Jun 15 21:04:20 2015 - 276: Haven't found "www.gnu.org" in hosts cache!
Mon Jun 15 21:04:20 2015 - 276: add new entry "www.gnu.org" of type GETAI for hosts to cache (first)
--8<---------------cut here---------------end--------------->8---

For subsequent requests, it shows fewer details, meaning that the cached
failure is used:

--8<---------------cut here---------------start------------->8---
Mon Jun 15 21:04:25 2015 - 276: handle_request: request received (Version = 2) from PID 297
Mon Jun 15 21:04:25 2015 - 276: 	GETFDHST
Mon Jun 15 21:04:25 2015 - 276: provide access to FD 6, for hosts
--8<---------------cut here---------------end--------------->8---

Twenty seconds after the original failure, we see:

--8<---------------cut here---------------start------------->8---
Mon Jun 15 21:04:40 2015 - 276: pruning hosts cache; time 1434395080
Mon Jun 15 21:04:40 2015 - 276: considering GETAI entry "www.gnu.org", timeout 1434395080
--8<---------------cut here---------------end--------------->8---

So cache expiry seems to be working as expected.

Now, if we enable networking with “dhclient -v eth0” and see what
happens, we get again a series of lookup failures, even after the
www.gnu.org entry has been removed from cache; apparently new failures
get cached.  Eventually, after a bunch of cache prunes (so a few times
20 seconds), lookup succeeds.

The situation is different if you use ‘getent hosts’ instead of ‘ping’–
note that the latter uses getaddrinfo whereas the former uses
gethostbyname{,v6}, which is cached differently.  Here we get a
successful lookup within 20 seconds after networking has been put up.

So my guess is that the GETAI cache is racy or something.

I’ve run nscd with Helgrind, which reports a few things (see attached
file), but I suspect most of it are false positives.

Ludo’.


[-- Attachment #2: Helgrind log --]
[-- Type: text/plain, Size: 26276 bytes --]

==336== Helgrind, a thread error detector
==336== Copyright (C) 2007-2013, and GNU GPL'd, by OpenWorks LLP et al.
==336== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info
==336== Command: nscd -f /gnu/store/8mhn4b3r0pg18lycwnnn9ms5jwr9wvfm-nscd.conf
==336== Parent PID: 291
==336== 
==337== Warning: invalid file descriptor 1024 in syscall close()
==337== Warning: invalid file descriptor 1025 in syscall close()
==337== Warning: invalid file descriptor 1026 in syscall close()
==337== Warning: invalid file descriptor 1027 in syscall close()
==337==    Use --log-fd=<number> to select an alternative log fd.
==337== Warning: invalid file descriptor 1028 in syscall close()
==337== Warning: invalid file descriptor 1029 in syscall close()
==336== 
==336== For counts of detected and suppressed errors, rerun with: -v
==336== Use --history-level=approx or =none to gain increased speed, at
==336== the cost of reduced accuracy of conflicting-access information
==336== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
==337== ---Thread-Announcement------------------------------------------
==337== 
==337== Thread #1 is the program's root thread
==337== 
==337== ----------------------------------------------------------------
==337== 
==337== Thread #1: pthread_cond_{signal,broadcast}: dubious: associated lock is not held by any thread
==337==    at 0x4C2A963: pthread_cond_signal_WRK (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4C2E18C: pthread_cond_signal@* (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x10E89A: fd_ready (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10F81E: main_loop_epoll (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x111E57: start_threads (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10D79D: main (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337== 
==337== ---Thread-Announcement------------------------------------------
==337== 
==337== Thread #7 was created
==337==    at 0x5352E9E: clone (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libc-2.21.so)
==337==    by 0x4E3E1D7: create_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==    by 0x4E3FBB4: pthread_create@@GLIBC_2.2.5 (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==    by 0x4C2C55B: pthread_create_WRK (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4C2D49B: pthread_create@* (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x111DD7: start_threads (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10D79D: main (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337== 
==337== ----------------------------------------------------------------
==337== 
==337== Thread #7: pthread_cond_{signal,broadcast}: dubious: associated lock is not held by any thread
==337==    at 0x4C2A963: pthread_cond_signal_WRK (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4C2E18C: pthread_cond_signal@* (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x118A9C: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x11AD6D: addhstaiX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x11BB43: addhstai (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF76: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== ---Thread-Announcement------------------------------------------
==337== 
==337== Thread #4 was created
==337==    at 0x5352E9E: clone (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libc-2.21.so)
==337==    by 0x4E3E1D7: create_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==    by 0x4E3FBB4: pthread_create@@GLIBC_2.2.5 (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==    by 0x4C2C55B: pthread_create_WRK (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4C2D49B: pthread_create@* (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x111DD7: start_threads (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10D79D: main (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337== 
==337== ---Thread-Announcement------------------------------------------
==337== 
==337== Thread #5 was created
==337==    at 0x5352E9E: clone (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libc-2.21.so)
==337==    by 0x4E3E1D7: create_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==    by 0x4E3FBB4: pthread_create@@GLIBC_2.2.5 (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==    by 0x4C2C55B: pthread_create_WRK (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4C2D49B: pthread_create@* (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x111DD7: start_threads (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10D79D: main (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337== 
==337== ----------------------------------------------------------------
==337== 
==337== Possible data race during read of size 1 at 0x329990 by thread #4
==337== Locks held: none
==337==    at 0x115CDA: getservbyname_r (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116198: lookup (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C36: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== This conflicts with a previous write of size 1 by thread #5
==337== Locks held: none
==337==    at 0x115E6E: getservbyname_r (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116198: lookup (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C36: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==  Address 0x329990 is 0 bytes inside data symbol "startp_initialized.11280"
==337== 
==337== ----------------------------------------------------------------
==337== 
==337== Possible data race during read of size 8 at 0x329980 by thread #4
==337== Locks held: none
==337==    at 0x115CF0: getservbyname_r (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116198: lookup (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C36: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== This conflicts with a previous write of size 8 by thread #5
==337== Locks held: none
==337==    at 0x115E4E: getservbyname_r (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116198: lookup (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C36: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==  Address 0x329980 is 0 bytes inside data symbol "start_fct.11282"
==337== 
==337== ----------------------------------------------------------------
==337== 
==337== Possible data race during read of size 8 at 0x329988 by thread #4
==337== Locks held: none
==337==    at 0x115CF7: getservbyname_r (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116198: lookup (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C36: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== This conflicts with a previous write of size 8 by thread #5
==337== Locks held: none
==337==    at 0x115E67: getservbyname_r (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116198: lookup (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C36: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==  Address 0x329988 is 0 bytes inside data symbol "startp.11281"
==337== 
==337== ----------------------------------------------------------------
==337== 
==337==  Lock at 0x3295F0 was first observed
==337==    at 0x4C2D7E9: pthread_mutex_init (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x110927: nscd_init (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10D798: main (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==  Address 0x3295f0 is 1392 bytes inside data symbol "dbs"
==337== 
==337== Possible data race during write of size 4 at 0x8449030 by thread #4
==337== Locks held: 1, at address 0x3295F0
==337==    at 0x11A64A: mempool_alloc (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x11692F: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== This conflicts with a previous read of size 4 by thread #5
==337== Locks held: none
==337==    at 0x4E46C1D: ??? (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==    by 0x1169BE: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==  Address 0x8449030 is not stack'd, malloc'd or on a free list
==337== 
==337== ----------------------------------------------------------------
==337== 
==337== Thread #5: pthread_cond_{signal,broadcast}: dubious: associated lock is not held by any thread
==337==    at 0x4C2A963: pthread_cond_signal_WRK (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4C2E18C: pthread_cond_signal@* (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x118A9C: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116868: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== ----------------------------------------------------------------
==337== 
==337==  Lock at 0x3295F0 was first observed
==337==    at 0x4C2D7E9: pthread_mutex_init (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x110927: nscd_init (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10D798: main (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==  Address 0x3295f0 is 1392 bytes inside data symbol "dbs"
==337== 
==337== Possible data race during write of size 4 at 0x8449030 by thread #4
==337== Locks held: 1, at address 0x3295F0
==337==    at 0x11A64A: mempool_alloc (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x118967: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x11661C: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== This conflicts with a previous read of size 4 by thread #5
==337== Locks held: none
==337==    at 0x118999: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116868: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==  Address 0x8449030 is not stack'd, malloc'd or on a free list
==337== 
==337== ----------------------------------------------------------------
==337== 
==337== Possible data race during write of size 8 at 0x8449050 by thread #4
==337== Locks held: none
==337==    at 0x118A0B: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x11661C: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== This conflicts with a previous read of size 8 by thread #5
==337== Locks held: none
==337==    at 0x4E46C1D: ??? (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==    by 0x118AC1: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116868: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==  Address 0x8449050 is not stack'd, malloc'd or on a free list
==337== 
==337== ----------------------------------------------------------------
==337== 
==337== Possible data race during read of size 4 at 0x8449038 by thread #4
==337== Locks held: none
==337==    at 0x118A17: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x11661C: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== This conflicts with a previous write of size 4 by thread #5
==337== Locks held: none
==337==    at 0x118A23: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116868: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==  Address 0x8449038 is not stack'd, malloc'd or on a free list
==337== 
==337== ----------------------------------------------------------------
==337== 
==337== Possible data race during write of size 4 at 0x8449038 by thread #4
==337== Locks held: none
==337==    at 0x118A23: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x11661C: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== This conflicts with a previous write of size 4 by thread #5
==337== Locks held: none
==337==    at 0x118A23: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116868: cache_addserv (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116C70: addservbyX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x116D33: addservbyname (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF40: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337==  Address 0x8449038 is not stack'd, malloc'd or on a free list
==337== 
==337== ----------------------------------------------------------------
==337== 
==337== Thread #4: pthread_cond_{signal,broadcast}: dubious: associated lock is not held by any thread
==337==    at 0x4C2A963: pthread_cond_signal_WRK (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4C2E18C: pthread_cond_signal@* (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x118A9C: cache_add (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x11AD6D: addhstaiX (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x11BB43: addhstai (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x10FF76: nscd_run_worker (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/sbin/nscd)
==337==    by 0x4C2C6E1: mythread_wrapper (in /gnu/store/apnmjac0aa0q6y78ynvasmlkljdfjcxv-valgrind-3.10.1/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==337==    by 0x4E3F463: start_thread (in /gnu/store/hy2hi0zj5hrqkmkhpdxf04c9bcnlnsf9-glibc-2.21/lib/libpthread-2.21.so)
==337== 
==337== 
==337== For counts of detected and suppressed errors, rerun with: -v
==337== Use --history-level=approx or =none to gain increased speed, at
==337== the cost of reduced accuracy of conflicting-access information
==337== ERROR SUMMARY: 124 errors from 12 contexts (suppressed: 14313 from 349)

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2015-06-15 20:12 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-06-15  2:43 bug#20816: Excessive negative cache time for DNS lookups Mark H Weaver
2015-06-15 13:15 ` Thompson, David
2015-06-15 20:02 ` Ludovic Courtès

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