Excessive negative cache time for DNS lookups

OpenSubmitted by Mark H Weaver.
Details
3 participants
  • Thompson, David
  • Ludovic Courtès
  • Mark H Weaver
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unassigned
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normal
M
M
Mark H Weaver wrote on 15 Jun 2015 04:43
(address . bug-guix@gnu.org)
87si9titcm.fsf@netris.org
On my GuixSD system, DNS lookup failures (due to lack of network) arecached for at least 4 minutes, and possibly much longer (I've not hadthe patience to wait until it expires).
Even after restarting nscd, the negative cache entry persists for aboutanother 20 seconds.
I run into this problem quite frequently after waking my system up fromsuspend-to-ram. It typically takes several seconds for wicd toestablish a network connection, and if I make the mistake of triggeringa name lookup of my server (world.peace.net), then I must do thefollowing:
(1) deco restart nscd(2) wait about 20 seconds
Looking at %nscd-default-caches in (gnu services base), I see that theintent is to cache host lookup failures for 20 seconds, and servicelookup failures for an hour. The fact that the negative cache entrypersists for 20 seconds after restarting nscd would seem to indicatethat nscd considers this to be a host lookup. So perhaps this is a bugin nscd.
Is anyone else able to reproduce this problem?
Mark
T
T
Thompson, David wrote on 15 Jun 2015 15:15
(name . Mark H Weaver)(address . mhw@netris.org)(address . 20816@debbugs.gnu.org)
CAJ=RwfYU6HK8XDxgxnnjipoC7SGJvic1A5zOShWb68T3+AbPOw@mail.gmail.com
On Sun, Jun 14, 2015 at 10:43 PM, Mark H Weaver <mhw@netris.org> wrote:
Toggle quote (25 lines)> 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 wirelessnetwork connectivity problems.
- Dave
L
L
Ludovic Courtès wrote on 15 Jun 2015 22:02
(name . Mark H Weaver)(address . mhw@netris.org)(address . 20816@debbugs.gnu.org)
874mm891ud.fsf@inria.fr
Mark H Weaver <mhw@netris.org> skribis:
Toggle quote (7 lines)> 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:
Toggle snippet (24 lines)(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)))
Then I had one console running “tail -f /var/log/nscd.log”, and anotherone 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:
Toggle snippet (6 lines)Mon Jun 15 21:04:20 2015 - 276: handle_request: request received (Version = 2) from PID 296Mon 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)
For subsequent requests, it shows fewer details, meaning that the cachedfailure is used:
Toggle snippet (5 lines)Mon Jun 15 21:04:25 2015 - 276: handle_request: request received (Version = 2) from PID 297Mon Jun 15 21:04:25 2015 - 276: GETFDHSTMon Jun 15 21:04:25 2015 - 276: provide access to FD 6, for hosts
Twenty seconds after the original failure, we see:
Toggle snippet (4 lines)Mon Jun 15 21:04:40 2015 - 276: pruning hosts cache; time 1434395080Mon Jun 15 21:04:40 2015 - 276: considering GETAI entry "www.gnu.org", timeout 1434395080
So cache expiry seems to be working as expected.
Now, if we enable networking with “dhclient -v eth0” and see whathappens, we get again a series of lookup failures, even after thewww.gnu.org entry has been removed from cache; apparently new failuresget cached. Eventually, after a bunch of cache prunes (so a few times20 seconds), lookup succeeds.
The situation is different if you use ‘getent hosts’ instead of ‘ping’–note that the latter uses getaddrinfo whereas the former usesgethostbyname{,v6}, which is cached differently. Here we get asuccessful 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 attachedfile), but I suspect most of it are false positives.
Ludo’.
==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)
?