stress test segfault in malloc

(gdb) where

#0  0x0000003788a78c33 in _int_malloc () from /lib64/libc.so.6

WT-1  0x0000003788a79fff in _int_memalign () from /lib64/libc.so.6

WT-2  0x0000003788a7a702 in memalign () from /lib64/libc.so.6

WT-3  0x0000003788a7a919 in posix_memalign () from /lib64/libc.so.6

WT-4  0x000000000042b39d in __wt_realloc_aligned (session=0x18a6f60,

    bytes_allocated_ret=0x7fc17cdf99f0, bytes_to_allocate=512,

    retp=0x7fc17cdf99e8) at ../src/os_posix/os_alloc.c:139

WT-5  0x0000000000444533 in __wt_buf_grow (session=0x18a6f60,

    buf=0x7fc17cdf99d0, size=512) at ../src/support/scratch.c:64

WT-6  0x0000000000444629 in __wt_buf_init (session=0x18a6f60,

    buf=0x7fc17cdf99d0, size=512) at ../src/support/scratch.c:100

WT-7  0x000000000049fb8b in __wt_block_read_off (session=0x18a6f60,

    block=0x7fc1281d8fd0, buf=0x7fc17cdf99d0, offset=169040896, size=512,

    cksum=651204990) at ../src/block/block_read.c:170

WT-8  0x000000000049f9f7 in __wt_bm_read (bm=0x7fc1281d8ed0, session=0x18a6f60,

    buf=0x7fc17cdf99d0,

    addr=0x7fc1900252da "\343\004\351m\201\344&\320y>\305\060\060\060\060\060\061\063\062\070\067.00/opqrstuvwxyzabcdefghijklmnopqrstuvw \212\343\004˹\201\344\356\255\363\026P\253\060\060\060\060\060\061\063\062\071\071.00/opqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabc \212\343\004\333\177\201\344a\276\345\225)000001"..., addr_size=10)

    at ../src/block/block_read.c:119

############################################

#  RUN PARAMETERS

############################################

auto_throttle=1

firstfit=0

# bitcnt not applicable to this run

bloom=1

bloom_bit_count=39

bloom_hash_count=11

bloom_oldest=0

cache=1

checksum=off

chunk_size=4

compaction=0

compression=none

data_extend=0

data_source=file

delete_pct=2

dictionary=0

file_type=row-store

hot_backups=0

huffman_key=0

huffman_value=0

insert_pct=13

internal_key_truncation=1

internal_page_max=14

key_gap=11

key_max=116

key_min=21

leaf_page_max=9

merge_max=16

merge_threads=3

ops=100000

prefix_compression=0

prefix_compression_min=2

repeat_data_pct=56

reverse=0

rows=100000

runs=100

split_pct=72

statistics=0

threads=27

value_max=1690

value_min=14

# wiredtiger_config not applicable to this run

write_pct=25

############################################