.
Thread 1 (Thread 0x7f923e0cba00 (LWP 886)):
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
        set = {__val = {0, 4399099348824, 208138993264557566, 140729709288544, 94441141612736, 94441132938696, 140729709288540, 94441132849189, 0, 94441132803402, 1, 38361475658, 5580634439008481872, 28259001035220079, 4673510122744735079, 140266095788559}}
        pid = <optimized out>
        tid = <optimized out>
        ret = <optimized out>
#1  0x00007f923eb24899 in __GI_abort () at abort.c:79
        save_stage = 1
        act = {__sigaction_handler = {sa_handler = 0x55e4ca289ad0 <cupsdReadClient>, sa_sigaction = 0x55e4ca289ad0 <cupsdReadClient>}, sa_mask = {__val = {94441141827696, 94441141831952, 94441132799338, 0, 4294967296, 94441142142304, 10980327644543381760, 0, 94441140727984, 94441141827696, 94441140727984, 94441141827696, 94441132939744, 140729709289040, 94441132556733, 15023190641950128175}}, sa_flags = -902932788, sa_restorer = 0x7ffe3054de4c}
        sigs = {__val = {32, 0 <repeats 15 times>}}
#2  0x00007f923eb8f38e in __libc_message (action=action@entry=do_abort, fmt=fmt@entry=0x7f923ecb83a5 "%s\n") at ../sysdeps/posix/libc_fatal.c:181
        ap = {{gp_offset = 24, fp_offset = 2842944107, overflow_arg_area = 0x7ffe3054df60, reg_save_area = 0x7ffe3054def0}}
        fd = 2
        list = <optimized out>
        nlist = <optimized out>
        cp = <optimized out>
        written = <optimized out>
#3  0x00007f923eb974dc in malloc_printerr (str=str@entry=0x7f923ecb652a "free(): invalid pointer") at malloc.c:5332
No locals.
#4  0x00007f923eb98cfc in _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at malloc.c:4173
        size = 4294967296
        fb = <optimized out>
        nextchunk = <optimized out>
        nextsize = <optimized out>
        nextinuse = <optimized out>
        prevsize = <optimized out>
        bck = <optimized out>
        fwd = <optimized out>
        __PRETTY_FUNCTION__ = "_int_free"
#5  0x00007f923ed9f02e in ipp_free_values (attr=attr@entry=0x55e4cab408e0, element=element@entry=0, count=1) at ipp.c:6440
        i = <optimized out>
        value = 0x55e4cab40900
#6  0x00007f923ed9ef93 in ippDelete (ipp=0x55e4cab848a0) at ipp.c:1759
        attr = 0x55e4cab408e0
        next = 0x55e4cab587d0
        attr = <optimized out>
        next = <optimized out>
#7  ippDelete (ipp=0x55e4cab848a0) at ipp.c:1733
        attr = <optimized out>
        next = <optimized out>
#8  0x000055e4ca28949c in cupsdWriteClient (con=0x55e4cab5f870) at client.c:2823
        bytes = <optimized out>
        field_col = <optimized out>
        bufptr = <optimized out>
        bufend = <optimized out>
        ipp_state = <optimized out>
#9  0x000055e4ca2c3a08 in cupsdDoSelect (timeout=<optimized out>) at select.c:489
        i = <optimized out>
        event = 0x7f923d500010
        nfds = 1
        fdptr = 0x55e4cabac560
        pfd = <optimized out>
        count = <optimized out>
#10 0x000055e4ca280b43 in main (argc=<optimized out>, argv=<optimized out>) at main.c:840
        i = 2
        opt = <optimized out>
        close_all = <optimized out>
        disconnect = <optimized out>
        fg = <optimized out>
        run_as_child = <optimized out>
        print_profile = <optimized out>
        fds = 1
        con = <optimized out>
        job = <optimized out>
        lis = <optimized out>
        current_time = <optimized out>
        activity = <optimized out>
        senddoc_time = 1569951690
        expire_time = 1569951695
        report_time = 0
        event_time = 1569951695
        timeout = 1
        limit = {rlim_cur = 524288, rlim_max = 524288}
        action = {__sigaction_handler = {sa_handler = 0x55e4ca2981f0 <sigterm_handler>, sa_sigaction = 0x55e4ca2981f0 <sigterm_handler>}, sa_mask = {__val = {81920, 0 <repeats 15 times>}}, sa_flags = 0, sa_restorer = 0x0}
        netif_time = 1569951680
        service_idle_exit = 0