(gdb) bt
#0  0x000000379880de78 in pwrite64 () from /lib64/libpthread.so.0
#1  0x0000000000471a3b in os_file_pwrite (file=4, buf=0x1c3a0000, n=1048576, offset=522190848, offset_high=1)
    at os/os0file.c:2127
#2  0x0000000000471ca4 in os_file_write (name=0x1bf063d8 "./ibdata1", file=4, buf=0x1c3a0000, offset=522190848, offset_high=1,
    n=1048576) at os/os0file.c:2591
#3  0x0000000000473159 in os_aio (type=11, mode=24, name=0x1bf063d8 "./ibdata1", file=4, buf=0x1c3a0000, offset=522190848,
    offset_high=1, n=1048576, message1=0x0, message2=0x0) at os/os0file.c:3580
#4  0x00000000004466bf in fil_extend_space_to_desired_size (actual_size=0x7fffdd8b6630, space_id=0, size_after_extend=75552832)
    at fil/fil0fil.c:3800
#5  0x0000000000447116 in fil_io (type=10, sync=1, space_id=0, block_offset=75552830, byte_offset=0, len=16384,
    buf=0x2aaaaaafc000, message=0x2aaab0ec3770) at fil/fil0fil.c:4236
#6  0x0000000000429333 in buf_read_page_low (err=0x7fffdd8b6720, sync=1, mode=132, space=0, tablespace_version=1,
    offset=75552830) at buf/buf0rea.c:171
#7  0x0000000000429a67 in buf_read_page (space=0, offset=75552830) at buf/buf0rea.c:362
#8  0x00000000004220ba in buf_page_get_gen (space=0, offset=75552830, rw_latch=2, guess=0x0, mode=10,
    file=0x528f20 "../../storage/innobase/include/trx0undo.ic", line=134, mtr=0x7fffdd8b69b0) at buf/buf0buf.c:1203
#9  0x00000000004cfbe3 in trx_undo_page_get (space=0, page_no=75552830, mtr=0x7fffdd8b69b0)
    at ../../storage/innobase/include/trx0undo.ic:134
#10 0x00000000004d2026 in trx_undo_mem_create_at_db_start (rseg=0x1c10e2a8, id=2, page_no=92169, mtr=0x7fffdd8b69b0)
    at trx/trx0undo.c:1277
#11 0x00000000004d2539 in trx_undo_lists_init (rseg=0x1c10e2a8) at trx/trx0undo.c:1350
#12 0x00000000004c87f7 in trx_rseg_mem_create (id=0, space=0, page_no=6, mtr=0x7fffdd8b6fa0) at trx/trx0rseg.c:160
#13 0x00000000004c8ea3 in trx_rseg_list_and_array_init (sys_header=0x2aaaaaae0026 "", mtr=0x7fffdd8b6fa0) at trx/trx0rseg.c:217
#14 0x00000000004cacd8 in trx_sys_init_at_db_start () at trx/trx0sys.c:915
#15 0x00000000004b98eb in innobase_start_or_create_for_mysql () at srv/srv0start.c:1528
#16 0x0000000000403849 in innodb_init () at xtrabackup.c:1901
#17 0x0000000000407638 in xtrabackup_prepare_func () at xtrabackup.c:4738
#18 0x000000000040a820 in main (argc=0, argv=0x1b306aa0) at xtrabackup.c:5376
(gdb)