Filter plugin memory leak with latest master build

[JeffLuoo]

Is your feature request related to a problem? Please describe.

A memory leak is detected when tested with valgrind.

[SERVICE]
    Flush                      1
    Log_Level                  debug
    Parsers_File               parsers.conf

[INPUT]
    Name              dummy
    Tag               k8s_container.test1.test2.test3
    dummy             {"key": 1, "sub": {"stream": "stdout", "id": "some id"}, "kubernetes": {"labels": {"team": "Santiago Wanderers"}}}

[FILTER]
    Name          record_modifier
    Match_Regex   *
    Record        test test

[OUTPUT]
    Name  stdout
    Match *

[email protected] ~/fluent-bit/build% sudo valgrind --leak-check=full ./bin/fluent-bit -c ../conf/in_dummy.conf
==2478901== Memcheck, a memory error detector
==2478901== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==2478901== Using Valgrind-3.16.1 and LibVEX; rerun with -h for copyright info
==2478901== Command: ./bin/fluent-bit -c ../conf/in_dummy.conf
==2478901== 
Fluent Bit v1.8.0
* Copyright (C) 2019-2021 The Fluent Bit Authors
* Copyright (C) 2015-2018 Treasure Data
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

[2021/03/09 16:59:02] [ info] Configuration:
[2021/03/09 16:59:02] [ info]  flush time     | 1.000000 seconds
[2021/03/09 16:59:02] [ info]  grace          | 5 seconds
[2021/03/09 16:59:02] [ info]  daemon         | 0
[2021/03/09 16:59:02] [ info] ___________
[2021/03/09 16:59:02] [ info]  inputs:
[2021/03/09 16:59:02] [ info]      dummy
[2021/03/09 16:59:02] [ info] ___________
[2021/03/09 16:59:02] [ info]  filters:
[2021/03/09 16:59:02] [ info]      record_modifier.0
[2021/03/09 16:59:02] [ info] ___________
[2021/03/09 16:59:02] [ info]  outputs:
[2021/03/09 16:59:02] [ info]      stdout.0
[2021/03/09 16:59:02] [ info] ___________
[2021/03/09 16:59:02] [ info]  collectors:
[2021/03/09 16:59:02] [ info] [engine] started (pid=2478901)
[2021/03/09 16:59:02] [debug] [engine] coroutine stack size: 24576 bytes (24.0K)
[2021/03/09 16:59:02] [debug] [storage] [cio stream] new stream registered: dummy.0
[2021/03/09 16:59:02] [ info] [storage] version=1.1.1, initializing...
[2021/03/09 16:59:02] [ info] [storage] in-memory
[2021/03/09 16:59:02] [ info] [storage] normal synchronization mode, checksum disabled, max_chunks_up=128
[2021/03/09 16:59:02] [ warn] [filter] NO match rule for record_modifier.0 filter instance, unloading.
[2021/03/09 16:59:02] [debug] [stdout:stdout.0] created event channels: read=18 write=19
[2021/03/09 16:59:02] [debug] [router] match rule dummy.0:stdout.0
[2021/03/09 16:59:02] [ info] [sp] stream processor started
[2021/03/09 16:59:04] [debug] [task] created task=0x5316d10 id=0 OK
[0] k8s_container.test1.test2.test3: [1615309143.704854634, {"key"=>1, "sub"=>{"stream"=>"stdout", "id"=>"some id"}, "kubernetes"=>{"labels"=>{"team"=>"Santiago Wanderers"}}}]
[2021/03/09 16:59:04] [debug] [out coro] cb_destroy coro_id=0
[2021/03/09 16:59:04] [debug] [task] destroy task=0x5316d10 (task_id=0)
[0] k8s_container.test1.test2.test3: [1615309144.726497477, {"key"=>1, "sub"=>{"stream"=>"stdout", "id"=>"some id"}, "kubernetes"=>{"labels"=>{"team"=>"Santiago Wanderers"}}}]
[2021/03/09 16:59:05] [debug] [task] created task=0x5369ce0 id=0 OK
[2021/03/09 16:59:05] [debug] [out coro] cb_destroy coro_id=1
[2021/03/09 16:59:05] [debug] [task] destroy task=0x5369ce0 (task_id=0)
[0] k8s_container.test1.test2.test3: [1615309145.691450227, {"key"=>1, "sub"=>{"stream"=>"stdout", "id"=>"some id"}, "kubernetes"=>{"labels"=>{"team"=>"Santiago Wanderers"}}}]
[2021/03/09 16:59:06] [debug] [task] created task=0x53bc7e0 id=0 OK
[2021/03/09 16:59:06] [debug] [out coro] cb_destroy coro_id=2
[2021/03/09 16:59:06] [debug] [task] destroy task=0x53bc7e0 (task_id=0)
[0] k8s_container.test1.test2.test3: [1615309146.691257140, {"key"=>1, "sub"=>{"stream"=>"stdout", "id"=>"some id"}, "kubernetes"=>{"labels"=>{"team"=>"Santiago Wanderers"}}}]
[2021/03/09 16:59:07] [debug] [task] created task=0x540f2e0 id=0 OK
[2021/03/09 16:59:07] [debug] [out coro] cb_destroy coro_id=3
[2021/03/09 16:59:07] [debug] [task] destroy task=0x540f2e0 (task_id=0)
^C[2021/03/09 16:59:08] [engine] caught signal (SIGINT)
[0] k8s_container.test1.test2.test3: [1615309147.691189030, {"key"=>1, "sub"=>{"stream"=>"stdout", "id"=>"some id"}, "kubernetes"=>{"labels"=>{"team"=>"Santiago Wanderers"}}}]
[2021/03/09 16:59:08] [debug] [task] created task=0x5461e30 id=0 OK
[2021/03/09 16:59:08] [ warn] [engine] service will stop in 5 seconds
[2021/03/09 16:59:08] [debug] [out coro] cb_destroy coro_id=4
[2021/03/09 16:59:08] [debug] [task] destroy task=0x5461e30 (task_id=0)
[2021/03/09 16:59:08] [debug] [input chunk] dummy.0 is paused, cannot append records
[2021/03/09 16:59:09] [debug] [input chunk] dummy.0 is paused, cannot append records
[2021/03/09 16:59:10] [debug] [input chunk] dummy.0 is paused, cannot append records
[2021/03/09 16:59:11] [debug] [input chunk] dummy.0 is paused, cannot append records
[2021/03/09 16:59:12] [ info] [engine] service stopped
==2478901== 
==2478901== HEAP SUMMARY:
==2478901==     in use at exit: 81 bytes in 3 blocks
==2478901==   total heap usage: 2,553 allocs, 2,550 frees, 2,095,806 bytes allocated
==2478901== 
==2478901== 81 (32 direct, 49 indirect) bytes in 1 blocks are definitely lost in loss record 3 of 3
==2478901==    at 0x483AB65: calloc (vg_replace_malloc.c:760)
==2478901==    by 0x19B4FE: flb_calloc (flb_mem.h:78)
==2478901==    by 0x19B580: flb_kv_item_create_len (flb_kv.c:37)
==2478901==    by 0x19B6C9: flb_kv_item_create (flb_kv.c:77)
==2478901==    by 0x16DA88: flb_filter_set_property (flb_filter.c:232)
==2478901==    by 0x1559B4: flb_service_conf (fluent-bit.c:830)
==2478901==    by 0x1560BB: flb_main (fluent-bit.c:1097)
==2478901==    by 0x15626A: main (fluent-bit.c:1170)
==2478901== 
==2478901== LEAK SUMMARY:
==2478901==    definitely lost: 32 bytes in 1 blocks
==2478901==    indirectly lost: 49 bytes in 2 blocks
==2478901==      possibly lost: 0 bytes in 0 blocks
==2478901==    still reachable: 0 bytes in 0 blocks
==2478901==         suppressed: 0 bytes in 0 blocks
==2478901== 
==2478901== For lists of detected and suppressed errors, rerun with: -s
==2478901== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

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Additional context

[nokute78]

I also reproduce it.

Note: Match_Regex property may affect.
Record test test is not released with Match_Regex property.

In contrast, this configuration is not leaked.
s/Match_Regex/Match/

[SERVICE]
    Flush                      1
    Log_Level                  debug
    Parsers_File               parsers.conf

[INPUT]
    Name              dummy
    Tag               k8s_container.test1.test2.test3
    dummy             {"key": 1, "sub": {"stream": "stdout", "id": "some id"}, "kubernetes": {"labels": {"team": "Santiago Wanderers"}}}

[FILTER]
    Name          record_modifier
    Match *   
#    Match_Regex   *
    Record        test test

[OUTPUT]
    Name  stdout
    Match *

[JeffLuoo]

@nokute78 Thank you for the reply!

[edsiper]

Thanks.

It was a leak when the plugin failed to initialize due to a wrong matching rule, just fixed in e312ef1

[JeffLuoo]

Thanks for the fix.