Re: BUG #19609: Server crashes when executing a JIT-compiled SQL function on s390x

Hello,
I am attaching the TAP test mentioned in the bug report.

The patch adds the self-contained reproducer as
src/test/modules/test_misc/t/014_jit_s390x.pl and registers it in the Meson
test list.

Best regards,
Artem Zarubin
Postgres Professional: https://postgrespro.com/

вт, 4 авг. 2026 г. в 19:28, PG Bug reporting form <noreply(at)postgresql(dot)org>:

> The following bug has been logged on the website:
>
> Bug reference: 19609
> Logged by: Artem Zarubin
> Email address: a(dot)prototype7(at)gmail(dot)com
> PostgreSQL version: 19beta2
> Operating system: Ubuntu 24.04.4 LTS (s390x)
> Description:
>
> Hello, I found a reproducible server crash when an SQL-language function is
> executed with LLVM JIT enabled on s390x.
>
> Tested commit:
>
> bad: 0392fb900eb89f52988cccd33046443c39c70d1c, PostgreSQL 19devel
>
> The server was built with:
>
> ./configure \
> --prefix=/home/test/pginstall-vanilla18 \
> --enable-debug \
> --enable-cassert \
> --with-llvm \
> LLVM_CONFIG=/usr/bin/llvm-config-18 \
> CLANG=/usr/bin/clang-18
>
> Environment:
>
> Architecture: s390x
> OS: Ubuntu 24.04.4 LTS
> Kernel: Linux 6.8.0-136-generic
> GCC: 13.3.0
> LLVM: 18.1.3
>
> The following parameters are used by the attached TAP test:
>
> restart_after_crash = on
> jit = on
>
> Minimal SQL script to reproduce:
>
> CREATE FUNCTION type_text(oid) RETURNS text
> LANGUAGE sql STABLE
> AS $$
> SELECT typname::text
> FROM pg_catalog.pg_type
> WHERE oid = $1
> $$;
>
> SET jit = on;
> SET jit_above_cost = 0;
> SET jit_inline_above_cost = -1;
> SET jit_optimize_above_cost = -1;
> SET jit_expressions = on;
> SET jit_tuple_deforming = off;
>
> SELECT count(*)
> FROM (
> SELECT oid
> FROM pg_catalog.pg_type
> ORDER BY oid
> LIMIT 7
> ) AS t
> WHERE type_text(t.oid) = 'int2vector';
>
> Expected result:
>
> count
> -------
> 1
> (1 row)
>
> Actual result:
>
> server closed the connection unexpectedly
> This probably means the server terminated abnormally before or while
> processing the request.
> connection to server was lost
>
> The server log contains:
>
> LOG: client backend (PID ...) was terminated by signal 11: Segmentation
> fault
> DETAIL: Failed process was running: SELECT count(*) ...
>
> Complete backtrace available from the core dump produced by the minimal
> reproducer:
>
> Program terminated with signal SIGSEGV, Segmentation fault.
> #0 0x000002aa3d0f29bc in cstring_to_text (s=0x0) at varlena.c:186
> #1 name_text (fcinfo=<optimized out>) at varlena.c:2709
> #2 0x000003ff9ae36126 in ?? ()
> Backtrace stopped: frame did not save the PC
>
> si_signo = 11 (SIGSEGV)
> si_code = 1 (SEGV_MAPERR)
> si_addr = 0x0
>
> r1 = 0x0
> r11 = 0x0
> pc = 0x2aa3d0f29bc <name_text+60>
>
> The frame above name_text() contains JIT-generated code without unwind
> information. name_text() receives a NULL C-string pointer and crashes in
> cstring_to_text().
>
> With jit=off, the same query completes successfully and returns 1. LLVM
> inlining and PostgreSQL's expensive-query JIT optimization tier are not
> required: the crash is also reproduced with jit_inline_above_cost and
> jit_optimize_above_cost set to -1.
>
> The attached patch adds the reproducer as
> src/test/modules/test_misc/t/014_jit_s390x.pl. From the PostgreSQL source
> tree, I ran it against the installed build with:
>
> PG_INSTALL=/home/test/pginstall-vanilla18
> PATH="$PG_INSTALL/bin:$PATH" \
> PERL5LIB="$PWD/src/test/perl" \
> PG_REGRESS="$PWD/src/test/regress/pg_regress" \
> prove -v src/test/modules/test_misc/t/014_jit_s390x.pl
>
> The TAP test fails as follows because the backend crashes:
>
> not ok 1 - JIT-compiled SQL function expression does not crash the
> backend
> got: '2'
> expected: '0'
> not ok 2 - JIT-compiled SQL function expression returns expected row
> got: ''
> expected: '1'
>
> The crash reproduced on every run of the final minimal test on this
> machine,
> including runs against newly initialized test clusters.
>
> ---
> Best regards,
> Artem Zarubin
> Postgres Professional: https://postgrespro.com/
>
>
>