Content-Type: multipart/mixed; boundary="------------Bl0sAphrH4PcNgZxIgDqpPRF"
Message-ID: <6c92f59b-f5bc-e58c-9bdd-d1f21c17c786@gmail.com>
Date: Mon, 21 Oct 2024 22:00:00 +0300
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.4.2
Subject: Re: race condition in pg_class
Content-Language: en-US
To: Noah Misch <noah@leadboat.com>
Cc: Nitin Motiani <nitinmotiani@google.com>,
 Heikki Linnakangas <hlinnaka@iki.fi>, Robert Haas <robertmhaas@gmail.com>,
 pgsql-hackers@postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>,
 Smolkin Grigory <smallkeen@gmail.com>, Michael Paquier <michael@paquier.xyz>
References: 
 <CAH5HC96yPfrLVQ-srZ65R73t_dBLNM4mCR-RGcT5zNa04DHSxA@mail.gmail.com>
 <20240903212329.61.nmisch@google.com>
 <CAH5HC96ASNkXyYVEG7pO98qr1WARGTohxGjVpBsu4c3hkM_OcA@mail.gmail.com>
 <20240904195720.cf.nmisch@google.com>
 <CAH5HC96ZwrjKF-RBijntw9uX2UzUtEKC3A7cxB_Xh8arVuKhKw@mail.gmail.com>
 <20240905220434.80.nmisch@google.com>
 <CAH5HC974+yieU=uTWPtpY1+irUZAY+5GiGKiXjfKhLzo+jsE+g@mail.gmail.com>
 <20240906185531.48.nmisch@google.com>
 <CAH5HC94xjj7JvRXD4LHVMgv=qVxuMm0On+2OvrGqeON4U-FTuQ@mail.gmail.com>
 <20240919213346.0a.nmisch@google.com> <20240924224352.93.nmisch@google.com>
From: Alexander Lakhin <exclusion@gmail.com>
In-Reply-To: <20240924224352.93.nmisch@google.com>
Archived-At: 
 <https://www.postgresql.org/message-id/6c92f59b-f5bc-e58c-9bdd-d1f21c17c786%40gmail.com>
Precedence: bulk

This is a multi-part message in MIME format.
--------------Bl0sAphrH4PcNgZxIgDqpPRF
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit

Hello Noah,

25.09.2024 01:43, Noah Misch wrote:
> Pushed, but the pushes contained at least one defect:
>

Please look at an anomaly introduced with a07e03fd8.
With the attached modification for intra-grant-inplace.spec, running this
test triggers a Valgrind-detected error for me:
==00:00:00:09.624 319033== Conditional jump or move depends on uninitialised value(s)
==00:00:00:09.624 319033==    at 0x25D120: DoesMultiXactIdConflict (heapam.c:7373)
==00:00:00:09.624 319033==    by 0x25B45A: heap_inplace_lock (heapam.c:6265)
==00:00:00:09.624 319033==    by 0x27D8CB: systable_inplace_update_begin (genam.c:867)
==00:00:00:09.624 319033==    by 0x33F717: index_update_stats (index.c:2856)
==00:00:00:09.624 319033==    by 0x33FEE2: index_build (index.c:3106)
==00:00:00:09.625 319033==    by 0x33C7D3: index_create (index.c:1276)
==00:00:00:09.625 319033==    by 0x451000: DefineIndex (indexcmds.c:1216)
==00:00:00:09.625 319033==    by 0x48D091: ATExecAddIndex (tablecmds.c:9156)
==00:00:00:09.625 319033==    by 0x483F8E: ATExecCmd (tablecmds.c:5302)
==00:00:00:09.625 319033==    by 0x483877: ATRewriteCatalogs (tablecmds.c:5186)
==00:00:00:09.625 319033==    by 0x482B9A: ATController (tablecmds.c:4741)
==00:00:00:09.625 319033==    by 0x4827A1: AlterTable (tablecmds.c:4387)
==00:00:00:09.625 319033==

Perhaps current_is_member in heap_inplace_lock() should be initialized
before the DoesMultiXactIdConflict() call as in other places...

Best regards,
Alexander
--------------Bl0sAphrH4PcNgZxIgDqpPRF
Content-Type: text/x-patch; charset=UTF-8;
 name="intra-grant-inplace-mod.patch"
Content-Disposition: attachment; filename="intra-grant-inplace-mod.patch"
Content-Transfer-Encoding: base64

ZGlmZiAtLWdpdCBhL3NyYy90ZXN0L2lzb2xhdGlvbi9zcGVjcy9pbnRyYS1ncmFudC1pbnBs
YWNlLnNwZWMgYi9zcmMvdGVzdC9pc29sYXRpb24vc3BlY3MvaW50cmEtZ3JhbnQtaW5wbGFj
ZS5zcGVjCmluZGV4IDI5OTJjODViNDQuLjMzMzljOWY0MDAgMTAwNjQ0Ci0tLSBhL3NyYy90
ZXN0L2lzb2xhdGlvbi9zcGVjcy9pbnRyYS1ncmFudC1pbnBsYWNlLnNwZWMKKysrIGIvc3Jj
L3Rlc3QvaXNvbGF0aW9uL3NwZWNzL2ludHJhLWdyYW50LWlucGxhY2Uuc3BlYwpAQCAtOTAs
OSArOTAsOSBAQCBwZXJtdXRhdGlvbgogCiAjIGlucGxhY2Ugd2FpdCBOTyBLRVkgVVBEQVRF
IHcvIEtFWSBTSEFSRQogcGVybXV0YXRpb24KLQlrZXlzaHI1CiAJYjMKIAlzZm5rdTMKKwlr
ZXlzaHI1CiAJYWRkazIocjMpCiAJcjMKIAo=

--------------Bl0sAphrH4PcNgZxIgDqpPRF--