BUG #14584: Segmentation fault importing large XML file

The following bug has been logged on the website:

Bug reference: 14584
Logged by: Jorge Solorzano
Email address: jorsol(at)gmail(dot)com
PostgreSQL version: 9.6.2
Operating system: Ubuntu 16.04 4.8.0-39-generic
Description:

I'm trying to import a large XML file into a table, for others (smaller)
xml, this works fine.

DROP TABLE IF EXISTS posts;
CREATE TABLE posts AS
SELECT
(xpath('@Id', x))[1]::text::integer "Id",
(xpath('@PostTypeId', x))[1]::text::integer "PostTypeId",
(xpath('@ParentId', x))[1]::text::integer "ParentId",
(xpath('@AcceptedAnswerId', x))[1]::text::integer "AcceptedAnswerId",
(xpath('@CreationDate', x))[1]::text::timestamp "CreationDate",
(xpath('@Score', x))[1]::text::integer "Score",
(xpath('@ViewCount', x))[1]::text::integer "ViewCount",
(xpath('@Body', x))[1]::text "Body",
(xpath('@OwnerUserId', x))[1]::text::integer "OwnerUserId",
(xpath('@LastEditorUserId', x))[1]::text::integer "LastEditorUserId",
(xpath('@LastEditDate', x))[1]::text::timestamp "LastEditDate",
(xpath('@LastActivityDate', x))[1]::text::timestamp "LastActivityDate",
(xpath('@Title', x))[1]::text "Title",
(xpath('@Tags', x))[1]::text "Tags",
(xpath('@AnswerCount', x))[1]::text::integer "AnswerCount",
(xpath('@CommentCount', x))[1]::text::integer "CommentCount",
(xpath('@FavoriteCount', x))[1]::text::integer "FavoriteCount",
(xpath('@ClosedDate', x))[1]::text::timestamp "ClosedDate"
FROM
unnest(xpath('/posts/row', xml_import('Posts.xml'))) x

This is what I get from the core dump:

Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x00007f3a0bcf9fb8 in ?? () from
/usr/lib/x86_64-linux-gnu/libxml2.so.2
(gdb) bt full
#0 0x00007f3a0bcf9fb8 in ?? () from
/usr/lib/x86_64-linux-gnu/libxml2.so.2
No symbol table info available.
#1 0x0000556dc268ba1c in xml_errorHandler (data=0x556dc2dba9b0,
error=<optimized out>) at
/build/postgresql-9.6-ZHxyhz/postgresql-9.6-9.6.2/build/../src/backend/utils/adt/xml.c:1661
errFuncSaved = 0x7f3a0bcfa1b0 <xmlGenericErrorDefaultFunc>
errCtxSaved = 0x0
xmlerrcxt = 0x556dc2dba9b0
ctxt = <optimized out>
input = 0x556dc2dc44b0
node = <optimized out>
name = <optimized out>
domain = <optimized out>
level = <optimized out>
errorBuf = 0x556dc2dbacc0
__func__ = "xml_errorHandler"
#2 0x00007f3a0bcfbfa4 in __xmlRaiseError () from
/usr/lib/x86_64-linux-gnu/libxml2.so.2
No symbol table info available.
#3 0x00007f3a0bd00900 in ?? () from
/usr/lib/x86_64-linux-gnu/libxml2.so.2
No symbol table info available.
#4 0x00007f3a0bd02f14 in ?? () from
/usr/lib/x86_64-linux-gnu/libxml2.so.2
No symbol table info available.
#5 0x00007f3a0bd17338 in xmlParseContent () from
/usr/lib/x86_64-linux-gnu/libxml2.so.2
No symbol table info available.
#6 0x00007f3a0bd17c13 in xmlParseElement () from
/usr/lib/x86_64-linux-gnu/libxml2.so.2
No symbol table info available.
#7 0x00007f3a0bd1866a in xmlParseDocument () from
/usr/lib/x86_64-linux-gnu/libxml2.so.2
No symbol table info available.
#8 0x00007f3a0bd1ffd9 in xmlCtxtReadMemory () from
/usr/lib/x86_64-linux-gnu/libxml2.so.2
No symbol table info available.
#9 0x0000556dc2690a26 in xpath_internal
(xpath_expr_text=xpath_expr_text(at)entry=0x556dc2d7dda0,
data=data(at)entry=0x7f380fa77040, namespaces=namespaces(at)entry=0x556dc2d7df90,

res_nitems=res_nitems(at)entry=0x0, astate=astate(at)entry=0x556dc2dda740) at
/build/postgresql-9.6-ZHxyhz/postgresql-9.6-9.6.2/build/../src/backend/utils/adt/xml.c:3842
save_exception_stack = 0x7fffea7f8000
save_context_stack = 0x0
local_sigjmp_buf = {{__jmpbuf = {10, -4817151912512283653,
93929908723104, 979473840, 93929908972784, 979473840, -4817151912059298821,
-1728720388456276997}, __mask_was_saved = 0,
__saved_mask = {__val = {0, 0, 0, 93929908723600,
11806714016570382336, 8388608, 139887287250280, 139887287250280,
93929908097440, 140737127610384, 93929901717430, 139887287250280,
93929908890240, 140737127610416, 93929901471218, 142}}}}
xmlerrcxt = 0x556dc2dba9b0
ctxt = 0x556dc2dc2e80
doc = 0x0
xpathctx = 0x0
xpathcomp = 0x0
xpathobj = 0x0
datastr = 0x7f380fa77044 "<?xml version=\"1.0\"
encoding=\"utf-8\"?>\n<posts>\n <row Id=\"1\" PostTypeId=\"1\"
AcceptedAnswerId=\"727273\" CreationDate=\"2009-07-15T06:27:46.723\"
Score=\"155\" ViewCount=\"92736\" Body=\"&lt;p&gt;A Vista virtua"...
len = 979473840
xpath_len = 10
string = 0x7f38becc5040 "<?xml version=\"1.0\"
encoding=\"utf-8\"?>\n<posts>\n <row Id=\"1\" PostTypeId=\"1\"
AcceptedAnswerId=\"727273\" CreationDate=\"2009-07-15T06:27:46.723\"
Score=\"155\" ViewCount=\"92736\" Body=\"&lt;p&gt;A Vista virtua"...
xpath_expr = 0x556dc2dbacf0 "/posts/row"
i = <optimized out>
ndim = <optimized out>
ns_names_uris = 0x0
ns_names_uris_nulls = 0x0
ns_count = 0
__func__ = "xpath_internal"
#10 0x0000556dc26918a8 in xpath (fcinfo=<optimized out>) at
/build/postgresql-9.6-ZHxyhz/postgresql-9.6-9.6.2/build/../src/backend/utils/adt/xml.c:3950
xpath_expr_text = 0x556dc2d7dda0
data = 0x7f380fa77040
namespaces = 0x556dc2d7df90
astate = 0x556dc2dda740