Corresponding backtrace:

#0  0x00007f24559c2418 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54
        resultvar = 0
        pid = 14605
        selftid = 14605
#1  0x00007f24559c401a in __GI_abort () at abort.c:89
        save_stage = 2
        act = {__sigaction_handler = {sa_handler = 0x66636666370a5d6b, sa_sigaction = 0x66636666370a5d6b}, sa_mask = {__val = {3256155514939455845, 7293972561931953719, 3255383588231721059, 3472328296227676272, 3472339291342909488, 2314885530818457632, 2314885530818453536, 2314885530818453536, 7022930802683944992, 7377853203759127922, 3256155514973010277, 7293972561931953719, 8659703141076316261, 3472328296227676272, 3472339291342909488, 2314885530818457632}}, sa_flags = 538976288, sa_restorer = 0x66}
        sigs = {__val = {32, 0 <repeats 15 times>}}
#2  0x00007f2455a0472a in __libc_message (do_abort=do_abort@entry=2, fmt=fmt@entry=0x7f2455b1d6b0 "*** Error in `%s': %s: 0x%s ***\n") at ../sysdeps/posix/libc_fatal.c:175
        ap = <error reading variable ap (Attempt to dereference a generic pointer.)>
        fd = 2
        on_2 = <optimized out>
        list = <optimized out>
        nlist = <optimized out>
        cp = <optimized out>
        written = <optimized out>
#3  0x00007f2455a0cf4a in malloc_printerr (ar_ptr=<optimized out>, ptr=<optimized out>, str=0x7f2455b1d7a0 "double free or corruption (top)", action=3) at malloc.c:5007
        buf = "0000558e1a5feac0"
        cp = <optimized out>
        ar_ptr = <optimized out>
        str = 0x7f2455b1d7a0 "double free or corruption (top)"
        action = 3
#4  _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at malloc.c:3868
        size = <optimized out>
        fb = <optimized out>
        nextchunk = <optimized out>
        nextsize = <optimized out>
        nextinuse = <optimized out>
        prevsize = <optimized out>
        bck = <optimized out>
        fwd = <optimized out>
        errstr = <optimized out>
        locked = <optimized out>
#5  0x00007f2455a10abc in __GI___libc_free (mem=<optimized out>) at malloc.c:2969
        ar_ptr = <optimized out>
        p = <optimized out>
        hook = <optimized out>
#6  0x0000558e1a28e833 in dns_packet_free (p=0x558e1a5feac0) at ../src/resolve/resolved-dns-packet.c:177
No locals.
#7  dns_packet_unref (p=0x558e1a5feac0) at ../src/resolve/resolved-dns-packet.c:189
        __PRETTY_FUNCTION__ = "dns_packet_unref"
#8  0x0000558e1a24de56 in dns_transaction_free (t=t@entry=0x558e1a5e1a70) at ../src/resolve/resolved-dns-transaction.c:87
        __func__ = "dns_transaction_free"
        __PRETTY_FUNCTION__ = "dns_transaction_free"
#9  0x0000558e1a24e42b in dns_transaction_gc (t=0x558e1a5e1a70) at ../src/resolve/resolved-dns-transaction.c:148
        t = 0x558e1a5e1a70
        __PRETTY_FUNCTION__ = "dns_transaction_gc"
#10 0x0000558e1a24e57f in dns_transaction_complete (t=0x558e1a5e1a70, state=<optimized out>) at ../src/resolve/resolved-dns-transaction.c:365
        st = <optimized out>
        key_str = "\034'\001\000\000\000\000\000\377\000\000\000\000\000\000\000\r\000\000\000\000\000\000\000\000\n]\032\216U\000\000\001\000\000\000\000\000\000\000\000\240\235\376\374\177\000\000\340\362+\032\216U\000\000\001\000\000\000\216U\000\000\001\000\000\000\000\000\000\000\020\000\000\000\000\000\000\000\021\000\000\000\000\000\000\000\001\000\000\000\216U\000\000\000\n]\032\216U\000\000@\022]\032\216U\000\000@\022]\032\216U\000\000\340\362+\032\216U\000\000\220\214^\032\216U\000\000\220\022_\032\216U\000\000@\022]\032\216U\000\000\340\362+\032\216U\000\000\220\214^\032\216U\000\000\a\000\000\000\000\000\000\000\f\000\000\000\000\000\000\000\000uG\036\215p\037\260\220\022_\032\216U\000\000"...
        __PRETTY_FUNCTION__ = "dns_transaction_complete"
        __func__ = "dns_transaction_complete"
#11 0x0000558e1a255cbd in dns_transaction_process_dnssec.lto_priv.425 (t=t@entry=0x558e1a5e1a70) at ../src/resolve/resolved-dns-transaction.c:720
        r = <optimized out>
        __PRETTY_FUNCTION__ = "dns_transaction_process_dnssec"
#12 0x0000558e1a256647 in dns_transaction_process_reply (t=t@entry=0x558e1a5e1a70, p=p@entry=0x558e1a5e3090) at ../src/resolve/resolved-dns-transaction.c:1002
        ts = 17926946249
        r = <optimized out>
        __PRETTY_FUNCTION__ = "dns_transaction_process_reply"
        __func__ = "dns_transaction_process_reply"
#13 0x0000558e1a25745b in on_dns_packet (s=<optimized out>, fd=<optimized out>, revents=<optimized out>, userdata=0x558e1a5e1a70) at ../src/resolve/resolved-dns-transaction.c:1053
        p = 0x558e1a5e3090
        t = 0x558e1a5e1a70
        r = <optimized out>
        __PRETTY_FUNCTION__ = "on_dns_packet"
        __func__ = "on_dns_packet"
#14 0x0000558e1a291563 in source_dispatch.lto_priv.501 (s=0x558e1a5fe910) at ../src/libsystemd/sd-event/sd-event.c:2268
        r = <optimized out>
        __PRETTY_FUNCTION__ = "source_dispatch"
        __func__ = "source_dispatch"
#15 0x0000558e1a22c7fc in sd_event_dispatch (e=0x558e1a5d21d0) at ../src/libsystemd/sd-event/sd-event.c:2629
        p = <optimized out>
        r = <optimized out>
#16 sd_event_run (timeout=18446744073709551615, e=0x558e1a5d21d0) at ../src/libsystemd/sd-event/sd-event.c:2688
        r = <optimized out>
#17 sd_event_loop (e=0x558e1a5d21d0) at ../src/libsystemd/sd-event/sd-event.c:2708
        r = <optimized out>
#18 main (argc=<optimized out>, argv=<optimized out>) at ../src/resolve/resolved.c:98
        m = 0x558e1a5d0660
        user = <optimized out>
        uid = <optimized out>
        gid = <optimized out>
        r = <optimized out>
        __func__ = "main"
        __PRETTY_FUNCTION__ = "main"