[pdal] seg-fault when compressing zero points with lazperf

[Andrew Bell]

Trying again... here's the ticket...
https://github.com/PDAL/PDAL/issues/3652

On Tue, Jan 18, 2022 at 9:54 AM Andrew Bell <andrew.bell.ia at gmail.com>
wrote:

> Here's the ticket...
>
> On Tue, Jan 18, 2022 at 9:52 AM Andrew Bell <andrew.bell.ia at gmail.com>
> wrote:
>
>> I've already fixed this, but I can't locate the PR right now. I'll write
>> again when I find it.
>>
>> On Tue, Jan 18, 2022 at 9:48 AM Jim Klassen <klassen.js at gmail.com> wrote:
>>
>>> It appears there is a seg-fault in pdal when compressing a file with
>>> zero points with lazperf.  Using laszip correctly creates an empty laz
>>> file.  With at least one point into the source file both laszip and lazperf
>>> work as expected.
>>>
>>> My guess is LazPerfVlrCompressorImpl::compress() is never getting
>>> called, so m_compressor is null, but that condition isn't being checked in
>>> LazPerfVlrCompressorImpl::done() before calling m_compress->done().  I'm
>>> not sure how much of LazPerfVlrCompressorImpl::done() should be skipped if
>>> m_compressor is null (there were no points to process).
>>>
>>>
>>> liblaszip: 3.4.1-6-gc7b67ca
>>> laz-perf: 3.0.0-1-g03ed832
>>> pdal: ac8068c7d
>>>
>>>
>>> $ cat lasperf.fail.txt
>>> X,Y,Z
>>>
>>> $ pdal info lasperf.fail.txt
>>> {
>>>    "file_size": 7,
>>>    "filename": "lasperf.fail.txt",
>>>    "now": "2022-01-18T08:19:08-0600",
>>>    "pdal_version": "2.3.0 (git-version: ac8068)",
>>>    "reader": "readers.text",
>>>    "stats":
>>>    {
>>>      "statistic":
>>>      [
>>>        {
>>>          "average": 0,
>>>          "count": 0,
>>>          "maximum": -1.797693135e+308,
>>>          "minimum": 1.797693135e+308,
>>>          "name": "X",
>>>          "position": 0,
>>>          "stddev": 0,
>>>          "variance": 0
>>>        },
>>>        {
>>>          "average": 0,
>>>          "count": 0,
>>>          "maximum": -1.797693135e+308,
>>>          "minimum": 1.797693135e+308,
>>>          "name": "Y",
>>>          "position": 1,
>>>          "stddev": 0,
>>>          "variance": 0
>>>        },
>>>        {
>>>          "average": 0,
>>>          "count": 0,
>>>          "maximum": -1.797693135e+308,
>>>          "minimum": 1.797693135e+308,
>>>          "name": "Z",
>>>          "position": 2,
>>>          "stddev": 0,
>>>          "variance": 0
>>>        }
>>>      ]
>>>    }
>>> }
>>> $ pdal translate lasperf.fail.txt lasperf.fail.laz
>>> --writers.las.compression=laszip
>>> $ pdal translate lasperf.fail.txt lasperf.fail.laz
>>> --writers.las.compression=lazperf
>>> Segmentation fault
>>> $ gdb --args pdal translate lasperf.fail.txt lasperf.fail.laz
>>> --writers.las.compression=lazperf
>>> GNU gdb (Debian 10.1-1.7) 10.1.90.20210103-git
>>> Copyright (C) 2021 Free Software Foundation, Inc.
>>> License GPLv3+: GNU GPL version 3 or later <
>>> http://gnu.org/licenses/gpl.html>
>>> This is free software: you are free to change and redistribute it.
>>> There is NO WARRANTY, to the extent permitted by law.
>>> Type "show copying" and "show warranty" for details.
>>> This GDB was configured as "x86_64-linux-gnu".
>>> Type "show configuration" for configuration details.
>>> For bug reporting instructions, please see:
>>> <https://www.gnu.org/software/gdb/bugs/>.
>>> Find the GDB manual and other documentation resources online at:
>>>      <http://www.gnu.org/software/gdb/documentation/>.
>>>
>>> For help, type "help".
>>> Type "apropos word" to search for commands related to "word"...
>>> Reading symbols from pdal...
>>> (No debugging symbols found in pdal)
>>> (gdb) run
>>> Starting program: /apps/PointClouds/pdal/2.3.0-ac8068c7d-laszip/bin/pdal
>>> translate lasperf.fail.txt lasperf.fail.laz
>>> --writers.las.compression=lazperf
>>> [Thread debugging using libthread_db enabled]
>>> Using host libthread_db library
>>> "/lib/x86_64-linux-gnu/libthread_db.so.1".
>>>
>>> Program received signal SIGSEGV, Segmentation fault.
>>> 0x00007ffff7e0c4d9 in pdal::LazPerfVlrCompressorImpl::done
>>> (this=0x4c2ea0)
>>>      at
>>> /apps/PointClouds/pdal/src/pdal/pdal/compression/LazPerfVlrCompression.cpp:101
>>> 101            m_compressor->done();
>>> (gdb) print m_compressor
>>> $1 = std::shared_ptr<lazperf::las_compressor> (empty) = {get() = 0x0}
>>> (gdb) quit
>>> A debugging session is active.
>>>
>>>      Inferior 1 [process 283225] will be killed.
>>>
>>> Quit anyway? (y or n) y
>>> $
>>>
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>>>
>>
>>
>> --
>> Andrew Bell
>> andrew.bell.ia at gmail.com
>>
>
>
> --
> Andrew Bell
> andrew.bell.ia at gmail.com
>


-- 
Andrew Bell
andrew.bell.ia at gmail.com
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