wt dump index:... causes segfault in __wt_raw_to_esc_hex

#define CHK(x) do {							\

	int __ret;							\

	if ((__ret = (x)) != 0) {					\

		fprintf(stderr, "ERROR at %s:%d: %s\n",			\

		    __FILE__, __LINE__, wiredtiger_strerror(__ret));	\

		exit(1);						\

	}								\

} while(0)

...

	home = "WT_HOME";

	CHK(system("rm -rf WT_HOME && mkdir WT_HOME"));

	CHK(wiredtiger_open(home, NULL, "create", &conn));

	CHK(conn->open_session(conn, NULL, NULL, &session));

	CHK(session->create(session, "table:main",

	    "key_format=i,value_format=i," "columns=(key,val)"));

        CHK(session->create(session, "index:main:ikey", "columns=(key)"));

        CHK(session->open_cursor(session, "table:main", NULL, NULL, &cursor));

	for (i = 1; i <= 3; i++) {

		sq = i*i;

		cube = i*i*i;

		cursor->set_key(cursor, i);

		cursor->set_value(cursor, sq, cube);

		CHK(cursor->insert(cursor));

	}

        CHK(cursor->close(cursor));

        CHK(session->close(session, NULL));

        CHK(conn->close(conn, NULL));

$ ../build_posix/.libs/wt -h WT_HOME/ dump index:main:ikey

WiredTiger Dump (WiredTiger Version 2.5.1)

Format=print

Header

index:main:ikey

allocation_size=4KB,app_metadata=,block_allocation=best,block_compressor=,cache_resident=0,checksum=uncompressed,colgroups=,collator=,columns=(key),dictionary=0,exclusive=0,extractor=,format=btree,huffman_key=,huffman_value=,immutable=0,internal_item_max=0,internal_key_max=0,internal_key_truncate=,internal_page_max=4KB,key_format=i,key_gap=10,leaf_item_max=0,leaf_key_max=0,leaf_page_max=32KB,leaf_value_max=0,lsm=(auto_throttle=,bloom=,bloom_bit_count=16,bloom_config=,bloom_hash_count=8,bloom_oldest=0,chunk_count_limit=0,chunk_max=5GB,chunk_size=10MB,merge_max=15,merge_min=0),memory_page_max=5MB,os_cache_dirty_max=0,os_cache_max=0,prefix_compression=0,prefix_compression_min=4,source="file:main_ikey.wti",split_deepen_min_child=0,split_deepen_per_child=0,split_pct=75,type=file,value_format=

Data

Segmentation fault: 11

$

* thread WT-1: tid = 0x1350c3d, 0x0000000109f2d012 libwiredtiger-2.5.1.dylib`__wt_raw_to_esc_hex(session=0x00007fd682808500, from=0x00007fd600000001, size=1, to=0x00007fd682500290) + 130 at hex.c:80, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x7fd600000001)

    frame #0: 0x0000000109f2d012 libwiredtiger-2.5.1.dylib`__wt_raw_to_esc_hex(session=0x00007fd682808500, from=0x00007fd600000001, size=1, to=0x00007fd682500290) + 130 at hex.c:80

   77  		 * trailing nul byte.

   78  		 */

   79  		for (p = from, t = to->mem, i = size; i > 0; --i, ++p)

-> 80  			if (isprint((int)*p)) {

   81  				if (*p == '\\')

   82  					*t++ = '\\';

   83  				*t++ = *p;

(lldb) p p

(const uint8_t *) $10 = 0x00007fd600000001 ""

(lldb) x/20x p

error: memory read failed for 0x7fd600000000

(lldb) p from

(const uint8_t *) $12 = 0x00007fd600000001 ""

(lldb) up

frame WT-1: 0x0000000109e91ba9 libwiredtiger-2.5.1.dylib`__raw_to_dump(session=0x00007fd682808500, from=0x00007fff55e0bef0, to=0x00007fd682500290, hexonly=0) + 137 at cur_dump.c:23

   20  		if (hexonly)

   21  			WT_RET(__wt_raw_to_hex(session, from->data, from->size, to));

   22  		else

-> 23  			WT_RET(

   24  			    __wt_raw_to_esc_hex(session, from->data, from->size, to));

   25

   26  		return (0);

(lldb) p *from

(WT_ITEM) $13 = (data = const void * = 0x00007fd600000001, size = 1, flags = 0, mem = void * = 0x0000000000000000, memsize = 140559289189632)