On (10/06/16 17:30), Jakub Hrozek wrote: >On Fri, Jun 10, 2016 at 04:42:51PM +0200, Lukas Slebodnik wrote: >> On (10/06/16 12:07), Sumit Bose wrote: >> >On Fri, Jun 10, 2016 at 11:09:49AM +0200, Lukas Slebodnik wrote: >> >> On (10/06/16 09:54), Sumit Bose wrote: >> >> >On Fri, Jun 10, 2016 at 09:26:38AM +0200, Lukas Slebodnik wrote: >> >> >> ehlo, >> >> >> >> >> >> I took some time to find out why pam-srv-tests fails so often. >> >> >> https://fedorahosted.org/sssd/ticket/2994 >> >> >> >> >> >> It is caused by slow execution of function sysdb_cache_password_ex. >> >> >> >> >> >> (Thu Jun 9 22:13:36:771048 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): start. >> >> >> (Thu Jun 9 22:13:36:771317 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): Before s3crypt_gen_salt >> >> >> (Thu Jun 9 22:13:36:771678 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): Before s3crypt_sha512 >> >> >> (Thu Jun 9 22:13:38:022470 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): Before sysdb_new_attrs >> >> >> (Thu Jun 9 22:13:38:023115 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): Before sysdb_attrs_add_string >> >> >> (Thu Jun 9 22:13:38:023431 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): Before sysdb_attrs_add_long >> >> >> (Thu Jun 9 22:13:38:023829 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): Before sysdb_attrs_add_long v2 >> >> >> (Thu Jun 9 22:13:38:024156 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): Before sysdb_attrs_add_long v3 >> >> >> (Thu Jun 9 22:13:38:024482 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): Before sysdb_attrs_add_uint32 >> >> >> (Thu Jun 9 22:13:38:024816 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): Before sysdb_set_user_attr >> >> >> (Thu Jun 9 22:13:38:035319 2016) [sssd] [sysdb_cache_password_ex] >> >> >> (0x0100): return eok >> >> >> >> >> >> As you can see, the execution of function s3crypt_sha512 >> >> >> took almost two seconds. >> >> >> >> >> >> Is it caused by valgrind all low entropy? >> >> > >> >> >The random data for the salt is already collected in s3crypt_gen_salt(). >> >> >sha512_crypt_r() basically mingles and password and the salt and does >> >> >hash operations. >> >> > >> >> >From a short inspection I can see nothing obvious which might cause such >> >> >delay. Maybe nspr_nss_init() if we really have to init NSS at this >> >> >point. The main operations in sha512_crypt_r() are heavily CPU bound, so >> >> >maybe some scheduler decides that its time for a different process to get >> >> >some CPU time? >> >> > >> >> >On the other hand can you give some details why the test fails because >> >> >of this delay? It looks a bit like we depend on a specific execution >> >> >time either in the test or the main code. If this is the case I think we >> >> >would make the code more robust by removing this dependency. >> >> > >> >> >> >> There are two possitive tests for pam authentication. >> >> test_pam_cached_auth_success and >> >> test_pam_cached_auth_success_combined_pw_with_cached_2fa >> >> >> >> The test case is: >> >> * simulate authenticate in pam responder -> common_test_pam_cached_auth >> >> * back-end should be contacted >> >> * store cached password (here is slow function sysdb_cache_password_ex) >> >> // we need to explicitely cache password because it is usually done in >> >> // back-end >> >> * simulate authenticate in pam responder -> common_test_pam_cached_auth >> >> * back-end should *NOT* be contacted >> >> >> >> However, the value of cached_auth_timeout is set to 2 seconds in tests. >> >> and therefore back-end is sometimes contected in second authentication. >> >> >> >> I tried to increase value of cached_auth_timeout 2 -> 4. >> >> It helped a little bit but after this change >> >> I can still see failures in pam-srv-tests but in differetn tests :-) >> >> >> >> [ FAILED ] test_pam_preauth_cert_nomatch >> >> [ FAILED ] test_pam_preauth_cert_match >> >> [ FAILED ] test_pam_preauth_cert_match_wrong_user >> >> [ FAILED ] test_pam_preauth_cert_no_logon_name >> >> >> >> and it does not make sense to me >> >> because it failes due to slow p11_child (30 seconds shoudl be enough >> >> for p11_child) >> > >> >yes, 30s should be enough. Even in the cases where p11_child returns >> >without a timeout it needs at least 10s to run trough an area of code >> >where among other things NSS is initialized. Does the error only happen >> >on RHEL6 or on other CI platforms as well? >> > >> hmm, I cannot reproduce anymore. >> >> Attached is a patch which increases a cached_auth_timeout. >> As Sumit already wrote: sha512_crypt_r() are heavily CPU bound >> So it might happen that it will slow with valgrind. >> >> I used just essential test-suit because I was >> interested only in valgrind test which caused problems. >> http://sssd-ci.duckdns.org/logs-test/job/0/88/summary.html >> http://sssd-ci.duckdns.org/logs-test/job/0/89/summary.html >> http://sssd-ci.duckdns.org/logs-test/job/0/90/summary.html >> http://sssd-ci.duckdns.org/logs-test/job/0/91/summary.html >> http://sssd-ci.duckdns.org/logs-test/job/0/92/summary.html >> http://sssd-ci.duckdns.org/logs-test/job/0/93/summary.html >> http://sssd-ci.duckdns.org/logs-test/job/0/94/summary.html >> http://sssd-ci.duckdns.org/logs-test/job/0/95/summary.html >> http://sssd-ci.duckdns.org/logs-test/job/0/96/summary.html >> http://sssd-ci.duckdns.org/logs-test/job/0/97/summary.html >> >> LS > >> From 7db9205d20244e810e4b497a7604696d956f790f Mon Sep 17 00:00:00 2001 >> From: Lukas Slebodnik <[email protected]> >> Date: Fri, 10 Jun 2016 09:28:37 +0200 >> Subject: [PATCH] pam-srv-tests: Increase cached_auth_timeout >> >> The execution sysdb_cache_password_ex can be slow >> due to function s3crypt_sha512 and valgrind slowdown. >> >> Therefore 2 seconds timeout can be reached >> in possitive tests test_pam_cached_auth_success >> and test_pam_cached_auth_success_combined_pw_with_cached_2fa >> >> Resolves: >> https://fedorahosted.org/sssd/ticket/2994 >> --- >> src/tests/cmocka/test_pam_srv.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) > >If this patch helped in your testing, then I say we should push it.. master: * 6574e41a8d1c2af293df2f57916628344eaa3560
LS _______________________________________________ sssd-devel mailing list [email protected] https://lists.fedorahosted.org/admin/lists/[email protected]
