Re: puzzling JSON bug - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: puzzling JSON bug
Date
Msg-id 515DD8BD.5050502@dunslane.net
Whole thread Raw
In response to Re: puzzling JSON bug  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On 04/04/2013 03:39 PM, Tom Lane wrote:
> Andrew Dunstan <andrew@dunslane.net> writes:
>> David Wheeler has presented me with a nasty bug case.
>> If I do this:
>>      select '{"members": { "add": [3, 4]}}'::json #> '{members,add}';
>> then I get a crash.
>> If I comment out the pfree() at json.c:parse_object_field() lines 378-9
>> then I get back the right result but instead get a warning like this:
>>      WARNING:  problem in alloc set ExprContext: bogus aset link in block
>>      0x1efaa80, chunk 0x1efb1f0
>> I'm not quite sure where I should go looking for what I've done wrong here.
> Routine array-overrun memory stomp.  The chunk header data for "fname"'s
> alloc chunk is being overwritten here:
>
> Watchpoint 2: *(int *) 1075253088
>
> Old value = 1074925616
> New value = -1
> 0x50fe14 in get_array_start (state=0x40170e88) at jsonfuncs.c:688
> 688                     _state->array_level_index[lex_level] = -1;
>
> It appears that lex_level is 2 but only enough room for 2 entries has
> been allocated in array_level_index[].


OK, many thanks, will fix.

cheers

andrew




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