Here is the backtrace with the above dummy plugin on the latest OpenLDAP (2.4.35):

Program received signal SIGABRT, Aborted. [Switching to Thread 0x7fffe34a3700 (LWP 15269)] 0x00007ffff5a32475 in *__GI_raise (sig=<optimized out>) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64 64 ../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory. (gdb) bt #0 0x00007ffff5a32475 in *__GI_raise (sig=<optimized out>) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64 #1 0x00007ffff5a356f0 in *__GI_abort () at abort.c:92 #2 0x00007ffff5a6d52b in __libc_message (do_abort=<optimized out>, fmt=<optimized out>) at ../sysdeps/unix/sysv/linux/libc_fatal.c:189 #3 0x00007ffff5a76d76 in malloc_printerr (action=3, str=0x7ffff5b4f170 "munmap_chunk(): invalid pointer", ptr=<optimized out>) at malloc.c:6283 #4 0x00007ffff63d214a in slapi_op_search_callback (op=0x7fffe34a0ff0, rs=<optimized out>, prc=<optimized out>) at ../../../../../servers/slapd/slapi/slapi_overlay.c:313 #5 slapi_op_search_callback (op=0x7fffe34a0ff0, rs=<optimized out>, prc=<optimized out>) at ../../../../../servers/slapd/slapi/slapi_overlay.c:296 #6 0x00007ffff63d304f in slapi_op_func (rs=0x7fffe34a0f80, op=<optimized out>) at ../../../../../servers/slapd/slapi/slapi_overlay.c:631 #7 slapi_op_func (op=0x7fffe34a0ff0, rs=0x7fffe34a0f80) at ../../../../../servers/slapd/slapi/slapi_overlay.c:556 #8 0x00005555555ff18a in overlay_op_walk (op=op@entry=0x7fffe34a0ff0, rs=0x7fffe34a0f80, which=op_search, oi=0x5555559e5680, on=0x5555559e43a0) at ../../../../servers/slapd/backover.c:661 #9 0x00005555555ff31b in over_op_func (op=0x7fffe34a0ff0, rs=<optimized out>, which=<optimized out>) at ../../../../servers/slapd/backover.c:723 #10 0x00007ffff1c4a45b in syncprov_findbase (op=op@entry=0x555555f093c0, fc=fc@entry=0x7fffe34a1290) at syncprov.c:465 #11 0x00007ffff1c4cd87 in syncprov_op_search (op=0x555555f093c0, rs=0x7fffe34a2a50) at syncprov.c:2461 #12 0x00005555555ff18a in overlay_op_walk (op=op@entry=0x555555f093c0, rs=rs@entry=0x7fffe34a2a50, which=which@entry=op_search, oi=0x5555559e5680, on=0x5555559bfbe0) at ../../../../servers/slapd/backover.c:661 #13 0x00007ffff63d3086 in slapi_op_func (rs=0x7fffe34a2a50, op=<optimized out>) at ../../../../../servers/slapd/slapi/slapi_overlay.c:647 #14 slapi_op_func (op=0x555555f093c0, rs=0x7fffe34a2a50) at ../../../../../servers/slapd/slapi/slapi_overlay.c:556 #15 0x00005555555ff18a in overlay_op_walk (op=op@entry=0x555555f093c0, rs=0x7fffe34a2a50, which=op_search, oi=0x5555559e5680, on=0x5555559e43a0) at ../../../../servers/slapd/backover.c:661 #16 0x00005555555ff31b in over_op_func (op=0x555555f093c0, rs=<optimized out>, which=<optimized out>) at ../../../../servers/slapd/backover.c:723 #17 0x0000555555594641 in fe_op_search (op=0x555555f093c0, rs=0x7fffe34a2a50) at ../../../../servers/slapd/search.c:402 #18 0x0000555555593f06 in do_search (op=0x555555f093c0, rs=0x7fffe34a2a50) at ../../../../servers/slapd/search.c:247 #19 0x0000555555591961 in connection_operation (ctx=ctx@entry=0x7fffe34a2ba0, arg_v=arg_v@entry=0x555555f093c0) at ../../../../servers/slapd/connection.c:1150 #20 0x0000555555591c84 in connection_read_thread (ctx=0x7fffe34a2ba0, argv=<optimized out>) at ../../../../servers/slapd/connection.c:1286 #21 0x00007ffff7b9dff3 in ?? () from /usr/lib/x86_64-linux-gnu/libldap_r-2.4.so.2 #22 0x00007ffff5d90b50 in start_thread (arg=<optimized out>) at pthread_create.c:304 #23 0x00007ffff5adaa7d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 #24 0x0000000000000000 in ?? () (gdb)