On 11/08/2026 09:32, Álvaro Herrera wrote:
On 2026-Aug-11, Masashi Kamura (Fujitsu) wrote:
We found that the program crashes when following the steps below.
1) Create the instance
initdb -D data --encoding=UTF8 --no-locale
2) Execute following SQL
SELECT to_date('01 ŞUB 2010', 'DD TMMON YYYY');
We are analyzing the cause and the following commit seems the cause.
https://github.com/postgres/postgres/commit/011384ba45f
Could you please check this?
I confirm that this crashes with my regular build options also, as long
as initdb --no-locale is used. The backtrace from the crash point is
#0 __GI___towupper_l (wc=74, locale=locale@entry=0x0) at
./wctype/wcfuncs_l.c:69
#1 0x0000563291e315b8 in strupper_libc_mb (dest=0x7ffe3664f100 "\002", destsize=80,
src=0x5632b0c066d8 "Jan",
srclen=3, locale=0x5632b0c02898) at
../../source/REL_18_STABLE/src/backend/utils/adt/pg_locale_libc.c:398
#2 strupper_libc (dst=dst@entry=0x7ffe3664f100 "\002", dstsize=dstsize@entry=80,
src=src@entry=0x5632b0c066d8 "Jan",
srclen=<optimized out>, locale=locale@entry=0x5632b0c02898)
at ../../source/REL_18_STABLE/src/backend/utils/adt/pg_locale_libc.c:147
#3 0x0000563291e2f029 in pg_strupper (dst=dst@entry=0x7ffe3664f100 "\002",
dstsize=dstsize@entry=80,
src=src@entry=0x5632b0c066d8 "Jan", srclen=<optimized out>,
locale=locale@entry=0x5632b0c02898)
at ../../source/REL_18_STABLE/src/backend/utils/adt/pg_locale.c:1325
The relevant code in src/backend/utils/adt/pg_locale_libc.c's
strupper_libc_mb() from frame 1 is
397 │ for (curr_char = 0; workspace[curr_char] != 0; curr_char++)
398 │ workspace[curr_char] = towupper_l(workspace[curr_char], loc);
where the important detail is that 'loc' is 0, which is not a valid
locale handle.
The locale code is quite the maze,
Indeed :-(.
but I'll see if I can find why is the locale object not
initialized.
For C locale, there is no locale object. Before commit 011384ba45f, none
of the callers called pg_strupper() with the C locale, they checked and
special-cased it and called asc_toupper() directly. See str_toupper().
Interestingly this only fails on REL_18_STABLE. On REL_19_STABLE,
pg_strupper() checks if locale->ctype is NULL, and does the equivalent
of asc_toupper() internally. On REL_17_STABLE and below didn't have
pg_strupper() so the equivalent of commit 011384ba45f uses str_toupper()
instead on those branches, which works.
I think the best fix is to make pg_strupper() in REL_18_STABLE also work
with the C locale. It's an accident waiting to happen if it doesn't.
(And same for all the other pg_str*() functions, of course)
- Heikki
