Crash releasing pooled PostgreSQL connection when layer table has column-restricted update privilege (?)

[strk]

What is the bug or the crash?

(gdb) bt
#0  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at ./nptl/pthread_kill.c:44
#1  0x00007ffff30a9e8f in __pthread_kill_internal (signo=6, threadid=<optimized out>) at ./nptl/pthread_kill.c:78
#2  0x00007ffff305afb2 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#3  0x00007ffff3045472 in __GI_abort () at ./stdlib/abort.c:79
#4  0x00005555555626df in qgisCrash(int) (signal=-1) at /usr/local/src/qgis/qgis/src/app/main.cpp:362
#5  0x0000555555562ed9 in myMessageOutput(QtMsgType, QMessageLogContext const&, QString const&) (type=QtFatalMsg, msg=...) at /usr/local/src/qgis/qgis/src/app/main.cpp:460
#6  0x00007ffff32c3b50 in  () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007ffff32c3c68 in  () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007ffff3290c60 in QMessageLogger::fatal(char const*, ...) const () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007ffff3290024 in qt_assert_x(char const*, char const*, char const*, int) () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007fffa60eb842 in QgsConnectionPool<QgsPostgresConn*, QgsPostgresConnPoolGroup>::releaseConnection(QgsPostgresConn*) (this=0x7fff94009940, conn=0x7fff5c001c00)
    at /usr/local/src/qgis/qgis/src/core/qgsconnectionpool.h:335
#11 0x00007fffa610bb93 in QgsPostgresFeatureIterator::close() (this=0x7fff5c0097f0) at /usr/local/src/qgis/qgis/src/providers/postgres/qgspostgresfeatureiterator.cpp:457

Steps to reproduce the issue

The way I've reproduced it was with a project file aimed at debugging GH-28835

The database was prepared like this:

CREATE TABLE qgis_issue_gh_28835 (
  id SERIAL PRIMARY KEY,
  restricted_column TEXT,
  geom GEOMETRY(Polygon, 4326)
);
GRANT USAGE
  ON qgis_issue_gh_28835_id_seq
  TO qgis_test_unprivileged_user;
GRANT SELECT, INSERT(geom), UPDATE(geom)
  ON qgis_issue_gh_28835
  TO qgis_test_unprivileged_user;

The project file is this: http://strk.kbt.io/tmp/qgis-infinite-crash-project.qgz

Taking out the UPDATE(geom) privilege fixes the crash.

Versions

ba1d45e

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

Relates to GH-28835