Stephane, I can't reproduce the hang on my test machine with gdb. (Despite your investigation seems right for me). CPU usage stay low, as usual on this machine (same slapd config than the production servers, but only 1 CPU is available).
To prove I made the right steps :-) : $ gdb --args ldapsearch ldaps://front -x [...] (gdb) break write Function "write" not defined. Make breakpoint pending on future shared library load? (y or [n]) y Breakpoint 1 (write) pending. (gdb) run Starting program: /usr/bin/ldapsearch ldaps://front -x conti [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". Breakpoint 1, __GI___libc_write (fd=3, buf=0x55555578b2f0, nbytes=14) at ../sysdeps/unix/sysv/linux/write.c:27 27 ../sysdeps/unix/sysv/linux/write.c: No such file or directory. (gdb) continue Continuing. Breakpoint 1, __GI___libc_write (fd=1, buf=0x55555578b2f0, nbytes=16) at ../sysdeps/unix/sysv/linux/write.c:27 27 in ../sysdeps/unix/sysv/linux/write.c Another information (maybe not important, or not related to this case): since monday, I started to migrate LDAP DB backend from BDB to LMDB. So I must wait next slapd hang to be sure DB change have no impact on this issue. (in the past there were sometimes 2 or 3 weeks elapsed between two slap hang). note: I reverted DB backend on my test machine but without reproducing the issue too -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to openldap in Ubuntu. https://bugs.launchpad.net/bugs/1926265 Title: slapd enter in infinite loop on sched_yield syscall Status in openldap package in Ubuntu: Confirmed Bug description: On a production server, sometimes slapd become unbresponsive, some threads loops in sched_yield syscall and consumme all CPU. To recover, slapd needs to restart. No related information is reported in log file. All same issues in OpenLDAP upstream project are old and fixed. So maybe this issue affects only Ubuntu package. It occurs randomly, so I have no steps to reproduce. OS : Bionic Openldap version: libldap-2.4-2:amd64 2.4.45+dfsg-1ubuntu1.10 libldap-common 2.4.45+dfsg-1ubuntu1.10 slapd 2.4.45+dfsg-1ubuntu1.10 Modules loaded: olcModuleLoad: {0}back_bdb olcModuleLoad: {1}syncprov olcModuleLoad: {2}back_monitor olcModuleLoad: {3}memberof.la olcModuleLoad: {4}refint.la olcModuleLoad: {5}rwm olcModuleload: {6}back_ldap Backend is BDB. slapd run in (single) master - (multi) slave mode. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/openldap/+bug/1926265/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
