Attaching to it, we're just polling in various threads and one was doing:

(gdb) info threads 
  Id   Target Id                                       Frame 
* 1    Thread 0x7ff453b2bb00 (LWP 2334) "cups-browsed" cupsArrayCurrent (a=0x56036f7aaae0)
    at /build/cups-h3QGh2/cups-2.4.2/cups/array.c:283
  2    Thread 0x7ff453aff6c0 (LWP 2360) "pool-spawner" syscall ()
    at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
  3    Thread 0x7ff44b2fe6c0 (LWP 2361) "gmain"        0x00007ff45590fd7f in __GI___poll (fds=0x56036f7a3440, 
    nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
  4    Thread 0x7ff4532fe6c0 (LWP 2362) "gdbus"        0x00007ff45590fd7f in __GI___poll (fds=0x7ff43c000b90, 
    nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29


#0  cupsArrayCurrent (a=0x56036f7aaae0) at /build/cups-h3QGh2/cups-2.4.2/cups/array.c:283
#1  0x00007ff455e4d4bb in cupsArrayNext (a=<optimized out>) at /build/cups-h3QGh2/cups-2.4.2/cups/array.c:828
#2  0x000056036efa5b2c in remove_printer_entry (p=0x7ff440029650) at daemon/cups-browsed.c:8137
#3  0x000056036efaa786 in update_cups_queues (unused=<optimized out>) at daemon/cups-browsed.c:9637
#4  0x00007ff455ae6a42 in g_timeout_dispatch
    (source=0x56036f7da260, callback=<optimized out>, user_data=<optimized out>) at ../../../glib/gmain.c:5054
#5  0x00007ff455ae636f in g_main_dispatch (context=0x56036f7aac90) at ../../../glib/gmain.c:3460
#6  g_main_context_dispatch (context=0x56036f7aac90) at ../../../glib/gmain.c:4200
#7  0x00007ff455b41178 in g_main_context_iterate.constprop.0
    (context=0x56036f7aac90, block=<optimized out>, dispatch=1, self=<optimized out>)
    at ../../../glib/gmain.c:4276
#8  0x00007ff455ae5bdf in g_main_loop_run (loop=0x56036f7ba6d0) at ../../../glib/gmain.c:4479
#9  0x000056036ef943ff in main (argc=<optimized out>, argv=<optimized out>) at daemon/cups-browsed.c:14077

Thread 1 "cups-browsed" received signal SIGINT, Interrupt.
cupsArrayNext (a=0x56036f7aaae0) at /build/cups-h3QGh2/cups-2.4.2/cups/array.c:813
813     /build/cups-h3QGh2/cups-2.4.2/cups/array.c: Bad file descriptor.                                           
(gdb) bt
#0  cupsArrayNext (a=0x56036f7aaae0) at /build/cups-h3QGh2/cups-2.4.2/cups/array.c:813
#1  0x000056036efaa0c4 in update_cups_queues (unused=<optimized out>) at daemon/cups-browsed.c:9310
#2  0x00007ff455ae6a42 in g_timeout_dispatch
    (source=0x56036f7da260, callback=<optimized out>, user_data=<optimized out>) at ../../../glib/gmain.c:5054
#3  0x00007ff455ae636f in g_main_dispatch (context=0x56036f7aac90) at ../../../glib/gmain.c:3460
#4  g_main_context_dispatch (context=0x56036f7aac90) at ../../../glib/gmain.c:4200
#5  0x00007ff455b41178 in g_main_context_iterate.constprop.0
    (context=0x56036f7aac90, block=<optimized out>, dispatch=1, self=<optimized out>)
    at ../../../glib/gmain.c:4276
#6  0x00007ff455ae5bdf in g_main_loop_run (loop=0x56036f7ba6d0) at ../../../glib/gmain.c:4479
#7  0x000056036ef943ff in main (argc=<optimized out>, argv=<optimized out>) at daemon/cups-browsed.c:14077

#0  0x00007ff45589dfd8 in _int_malloc (av=av@entry=0x7ff4559f6c80 <main_arena>, bytes=bytes@entry=4)
    at ./malloc/malloc.c:3839
#1  0x00007ff4558a0978 in __libc_calloc (n=n@entry=1, elem_size=elem_size@entry=4) at ./malloc/malloc.c:3664
#2  0x00007ff455aeb551 in g_malloc0 (n_bytes=4) at ../../../glib/gmem.c:163
#3  0x00007ff455aceae1 in g_hash_table_resize (hash_table=hash_table@entry=0x56036f7a36f0 = {...})
    at ../../../glib/ghash.c:885
#4  0x00007ff455ad1b8f in g_hash_table_maybe_resize (hash_table=0x56036f7a36f0 = {...})
    at ../../../glib/ghash.c:918
#5  g_hash_table_insert_node
    (hash_table=0x56036f7a36f0 = {...}, node_index=<optimized out>, key_hash=<optimized out>, new_key=<optimized out>, new_value=<optimized out>, keep_new_key=<optimized out>, reusing_key=0) at ../../../glib/ghash.c:1371
#6  0x00007ff455ad2768 in g_hash_table_insert_internal
    (keep_new_key=0, value=0x56036f7da260, key=0x98e30f6, hash_table=0x56036f7a36f0 = {...})
    at ../../../glib/ghash.c:1630
#7  g_hash_table_insert (hash_table=0x56036f7a36f0 = {...}, key=0x98e30f6, value=0x56036f7da260)
    at ../../../glib/ghash.c:1659
#8  0x00007ff455ae52e3 in g_source_attach_unlocked
    (source=source@entry=0x56036f7da260, context=context@entry=0x56036f7aac90, do_wakeup=do_wakeup@entry=1)
    at ../../../glib/gmain.c:1295
#9  0x00007ff455ae542a in g_source_attach (source=source@entry=0x56036f7da260, context=0x56036f7aac90, 
    context@entry=0x0) at ../../../glib/gmain.c:1369
#10 0x00007ff455ae6b77 in g_timeout_add_seconds_full
    (priority=priority@entry=0, interval=interval@entry=0, function=function@entry=0x56036efaa040 <update_cups_queues>, data=data@entry=0x0, notify=notify@entry=0x0) at ../../../glib/gmain.c:5354
#11 0x00007ff455ae6beb in g_timeout_add_seconds
    (interval=interval@entry=0, function=function@entry=0x56036efaa040 <update_cups_queues>, data=data@entry=0x0)
    at ../../../glib/gmain.c:5401
#12 0x000056036efa7e2d in recheck_timer () at daemon/cups-browsed.c:9683
#13 0x000056036efaa795 in update_cups_queues (unused=<optimized out>) at daemon/cups-browsed.c:9643
#14 0x00007ff455ae6a42 in g_timeout_dispatch
    (source=0x56036f7c4330, callback=<optimized out>, user_data=<optimized out>) at ../../../glib/gmain.c:5054
#15 0x00007ff455ae636f in g_main_dispatch (context=0x56036f7aac90) at ../../../glib/gmain.c:3460
#16 g_main_context_dispatch (context=0x56036f7aac90) at ../../../glib/gmain.c:4200
#17 0x00007ff455b41178 in g_main_context_iterate.constprop.0
    (context=0x56036f7aac90, block=<optimized out>, dispatch=1, self=<optimized out>)
    at ../../../glib/gmain.c:4276
#18 0x00007ff455ae5bdf in g_main_loop_run (loop=0x56036f7ba6d0) at ../../../glib/gmain.c:4479
#19 0x000056036ef943ff in main (argc=<optimized out>, argv=<optimized out>) at daemon/cups-browsed.c:14077


In frame 13:

(gdb) info locals
p = <optimized out>
q = <optimized out>
http = <optimized out>
uri = " \233zo\003V\000\000y\033kU\000\000\000\000\000\233zo\003V", '\000' <repeats 75 times>, ",\303U\364\177\000\000\0001\370\233H\234`P\3005vo\003V\000\000\003\000\000\000\000\000\000\000\300Y\370>\375\177\000\000X\221kU\364\177\000\000\000\000\000\000\000\000\000\000l\000\000\000\000\000\000\000ٱzo\003V\000\000\240\274iU\364\177\000\000\330X\370>\003\000\000\000\230Y\370>\375\177\000\000\340X\370>\375\177\000\000\223"...
num_jobs = <optimized out>
jobs = 0x0
request = <optimized out>
current_time = <optimized out>


#0  __libc_send (flags=<optimized out>, len=264, buf=0x56036f77ea78, fd=10)
    at ../sysdeps/unix/sysv/linux/send.c:28
#1  __libc_send (fd=10, buf=buf@entry=0x56036f77ea78, len=len@entry=264, flags=flags@entry=0)
    at ../sysdeps/unix/sysv/linux/send.c:23
#2  0x00007ff455e5f88a in http_write
    (http=http@entry=0x56036f77c280, buffer=buffer@entry=0x56036f77ea78 "POST /printers/abc HTTP/1.1\r\nAuthorization: PeerCred cups-browsed\r\nContent-Length: 156\r\nContent-Type: application/ipp\r\nDate: Fri, 05 May 2023 07:30:03 GMT\r\nHost: localhost:0\r\nUser-Agent: CUPS/2.4.2 (L"..., length=264)
    at /build/cups-h3QGh2/cups-2.4.2/cups/http.c:4749
#3  0x00007ff455e5f9cf in httpFlushWrite (http=http@entry=0x56036f77c280)
    at /build/cups-h3QGh2/cups-2.4.2/cups/http.c:706
#4  0x00007ff455e6240d in http_send (http=0x56036f77c280, request=<optimized out>, uri=<optimized out>)
    at /build/cups-h3QGh2/cups-2.4.2/cups/http.c:4453
#5  0x00007ff455e7bcba in cupsSendRequest
    (http=http@entry=0x56036f77c280, request=request@entry=0x7ff44012b0c0, resource=resource@entry=0x7ff42afcad70 "/printers/abc", length=length@entry=156) at /build/cups-h3QGh2/cups-2.4.2/cups/request.c:723
#6  0x00007ff455e7c143 in cupsDoIORequest
    (http=0x56036f77c280, request=0x7ff44012b0c0, resource=0x7ff42afcad70 "/printers/abc", infile=-1, outfile=-1)
    at /build/cups-h3QGh2/cups-2.4.2/cups/request.c:203
#7  0x00007ff455fa162c in cfGetPrinterAttributes5(http_t*, char const*, char const* const*, int, char const* const*, int, int, int*, int)
    (http_printer=http_printer@entry=0x56036f77c280, raw_uri=raw_uri@entry=0x7ff42afdba60 "ipp://localhost/printers/abc", pattrs=pattrs@entry=0x7ff42afdba50, pattrs_size=pattrs_size@entry=1, req_attrs=<optimized out>, 
    req_attrs@entry=0x7ff42afdba58, req_attrs_size=<optimized out>, 
    req_attrs_size@entry=1, debug=0, driverless_info=0x0, is_fax=0) at cupsfilters/ipp.c:361
#8  0x00007ff455fa1ca8 in cfGetPrinterAttributes3(http_t*, char const*, char const* const*, int, char const* const*, int, int, int*)
    (http_printer=http_printer@entry=0x56036f77c280, raw_uri=raw_uri@entry=0x7ff42afdba60 "ipp://localhost/printers/abc", pattrs=pattrs@entry=0x7ff42afdba50, pattrs_size=pattrs_size@entry=1, req_attrs=req_attrs@entry=0x7ff42afdba58, req_attrs_size=req_attrs_size@entry=1, debug=0, driverless_info=0x0) at cupsfilters/ipp.c:180
#9  0x00007ff455fa1d34 in cfGetPrinterAttributes2(http_t*, char const*, char const* const*, int, char const* const*, int, int)
    (http_printer=http_printer@entry=0x56036f77c280, raw_uri=raw_uri@entry=0x7ff42afdba60 "ipp://localhost/printers/abc", pattrs=pattrs@entry=0x7ff42afdba50, pattrs_size=pattrs_size@entry=1, req_attrs=req_attrs@entry=0x7ff42afdba58, req_attrs_size=req_attrs_size@entry=1, debug=0) at cupsfilters/ipp.c:163
#10 0x000056036ef9dc92 in get_printer_uuid
    (raw_uri=0x7ff42afdba60 "ipp://localhost/printers/abc", http_printer=0x56036f77c280)
    at daemon/cups-browsed.c:3992
#11 get_local_printers () at daemon/cups-browsed.c:4094
#12 0x000056036efa8ab5 in update_local_printers.part.0.lto_priv.0 () at daemon/cups-browsed.c:4383
#13 0x000056036efa407d in update_local_printers () at daemon/cups-browsed.c:4355
#14 get_local_queue_name
    (service_name=0x56036f7dcff0 "EPSON XP-255 257 Series 2 @ philw-mbp", make_model=0x7ff44002c150 "EPSON XP-255 257 Series", resource=0x7ff4401253c0 "printers/EPSON_XP_255_257_Series_2", remote_host=0x7ff4401322c0 "philw-mbp.local", is_cups_queue=0x7ff42afdc014, exclude=0x0) at daemon/cups-browsed.c:6213
#15 0x000056036efabb4c in examine_discovered_printer_record
    (host=<optimized out>, ip=ip@entry=0x0, port=port@entry=631, resource=0x7ff4401253c0 "printers/EPSON_XP_255_257_Series_2", service_name=service_name@entry=0x56036f7dcff0 "EPSON XP-255 257 Series 2 @ philw-mbp", location=<optimized out>, 
    location@entry=0x56036efb7994 "", info=0x7ff42afdca90 "EPSON XP-255 257 Series 2", type=0x56036f7d7110 "_ipp._tcp", domain=0x56036f7d6fe0 "local", interface=0x7ff42afdca70 "wlp0s20f3", family=10, txt=0x56036f7dd100)
    at daemon/cups-browsed.c:10405
#16 0x000056036efad54a in resolve_callback (arg=0x7ff43c003fc0) at daemon/cups-browsed.c:11091
#17 0x00007ff45588f18a in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:444
#18 0x00007ff45591dbd0 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81




---

Maybe a gsource not being removed and repeatdly running forever?