v3.2.6: assertion failures on Debian i386

[pitrou]

I've been testing the v3.2.6 release candidate on the Apache Arrow CI jobs, and we get assertion failures on Debian i386 (32-bit) on all our unit tests.

Here are the full logs:
https://productionresultssa8.blob.core.windows.net/actions-results/b9e69351-eb38-4866-afb7-37eeacd9a404/workflow-job-run-ce200fd7-7937-5c45-b048-66dd2b022568/logs/job/job-logs.txt?rsct=text%2Fplain&se=2026-01-12T10%3A10%3A04Z&sig=iRvbbY6wJbu4TPUqcYyoIfZlLJ3IQuZ%2BMBLFXFbgSg4%3D&ske=2026-01-12T18%3A52%3A42Z&skoid=ca7593d4-ee42-46cd-af88-8b886a2f84eb&sks=b&skt=2026-01-12T06%3A52%3A42Z&sktid=398a6654-997b-47e9-b12b-9515b896b4de&skv=2025-11-05&sp=r&spr=https&sr=b&st=2026-01-12T09%3A59%3A59Z&sv=2025-11-05

Here is an example crash log for clarity. It seems to happen at process shutdown:

2026-01-12T09:35:15.7210769Z Running arrow-extension-type-test, redirecting output into /build/cpp/build/test-logs/arrow-extension-type-test.txt (attempt 1/1)
2026-01-12T09:35:15.7214676Z /arrow/cpp/build-support/run-test.sh: line 88: 16282 Aborted                 (core dumped) $TEST_EXECUTABLE "$@" > $LOGFILE.raw 2>&1
2026-01-12T09:35:15.7216769Z Running main() from gmock_main.cc
2026-01-12T09:35:15.7217541Z [==========] Running 6 tests from 1 test suite.
2026-01-12T09:35:15.7218108Z [----------] Global test environment set-up.
2026-01-12T09:35:15.7218642Z [----------] 6 tests from TestExtensionType
2026-01-12T09:35:15.7219192Z [ RUN      ] TestExtensionType.ExtensionTypeTest
2026-01-12T09:35:15.7219796Z [       OK ] TestExtensionType.ExtensionTypeTest (0 ms)
2026-01-12T09:35:15.7220418Z [ RUN      ] TestExtensionType.IpcRoundtrip
2026-01-12T09:35:15.7220982Z [       OK ] TestExtensionType.IpcRoundtrip (5 ms)
2026-01-12T09:35:15.7221577Z [ RUN      ] TestExtensionType.UnrecognizedExtension
2026-01-12T09:35:15.7222227Z [       OK ] TestExtensionType.UnrecognizedExtension (0 ms)
2026-01-12T09:35:15.7222857Z [ RUN      ] TestExtensionType.ParametricTypes
2026-01-12T09:35:15.7223435Z [       OK ] TestExtensionType.ParametricTypes (1 ms)
2026-01-12T09:35:15.7224016Z [ RUN      ] TestExtensionType.ParametricEquals
2026-01-12T09:35:15.7224625Z [       OK ] TestExtensionType.ParametricEquals (0 ms)
2026-01-12T09:35:15.7225223Z [ RUN      ] TestExtensionType.ValidateExtensionArray
2026-01-12T09:35:15.7226158Z [       OK ] TestExtensionType.ValidateExtensionArray (1 ms)
2026-01-12T09:35:15.7226791Z [----------] 6 tests from TestExtensionType (9 ms total)
2026-01-12T09:35:15.7227172Z 
2026-01-12T09:35:15.7227351Z [----------] Global test environment tear-down
2026-01-12T09:35:15.7228210Z [==========] 6 tests from 1 test suite ran. (9 ms total)
2026-01-12T09:35:15.7228923Z [  PASSED  ] 6 tests.
2026-01-12T09:35:15.7229855Z mimalloc: assertion failed: at "/build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/bitmap.c":1453, _mi_bitmap_forall_setc_rangesn
2026-01-12T09:35:15.7230890Z   assertion: "rngslices <= MI_BFIELD_BITS"
2026-01-12T09:35:15.7231424Z !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2026-01-12T09:35:15.7232517Z Running '/build/cpp/debug/arrow-extension-type-test' produced core dump at '/tmp/core.arrow-extension.16282', printing backtrace:
2026-01-12T09:35:15.7233514Z [New LWP 16282]
2026-01-12T09:35:15.7233825Z [New LWP 16288]
2026-01-12T09:35:15.7234191Z [Thread debugging using libthread_db enabled]
2026-01-12T09:35:15.7234859Z Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1".
2026-01-12T09:35:15.7235669Z Core was generated by `/build/cpp/debug/arrow-extension-type-test'.
2026-01-12T09:35:15.7236510Z Program terminated with signal SIGABRT, Aborted.
2026-01-12T09:35:15.7237040Z #0  0xf262a579 in __kernel_vsyscall ()
2026-01-12T09:35:15.7237565Z [Current thread is 1 (Thread 0xecf5e200 (LWP 16282))]
2026-01-12T09:35:15.7237958Z 
2026-01-12T09:35:15.7238123Z Thread 2 (Thread 0xecbffb40 (LWP 16288)):
2026-01-12T09:35:15.7238590Z #0  0xf262a579 in __kernel_vsyscall ()
2026-01-12T09:35:15.7239124Z #1  0xee6dfdc2 in ?? () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7239741Z #2  0xee64e6d5 in ?? () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7240441Z #3  0xee65192e in pthread_cond_wait () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7241659Z #4  0xf117429f in background_thread_sleep (tsdn=0xecbff2b0, info=0xecc09b80, interval=18446744073709551615) at src/background_thread.c:137
2026-01-12T09:35:15.7243165Z #5  0xf117474c in background_work_sleep_once (tsdn=0xecbff2b0, info=0xecc09b80, ind=0) at src/background_thread.c:229
2026-01-12T09:35:15.7244334Z #6  0xf1174c69 in background_thread0_work (tsd=0xecbff2b0) at src/background_thread.c:374
2026-01-12T09:35:15.7245336Z #7  0xf1174eeb in background_work (tsd=0xecbff2b0, ind=0) at src/background_thread.c:412
2026-01-12T09:35:15.7276580Z #8  0xf1175074 in background_thread_entry (ind_arg=0x0) at src/background_thread.c:444
2026-01-12T09:35:15.7277426Z #9  0xee65248c in ?? () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7278078Z #10 0xee6eb616 in clone () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7278509Z 
2026-01-12T09:35:15.7278678Z Thread 1 (Thread 0xecf5e200 (LWP 16282)):
2026-01-12T09:35:15.7279154Z #0  0xf262a579 in __kernel_vsyscall ()
2026-01-12T09:35:15.7279676Z #1  0xee654457 in ?? () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7280324Z #2  0xee603121 in raise () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7280992Z #3  0xee5ec26a in abort () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7281912Z #4  0xf123e113 in _mi_assert_fail () at /build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/options.c:561
2026-01-12T09:35:15.7283202Z #5  0xf1238c77 in _mi_bitmap_forall_setc_rangesn () at /build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/bitmap.c:1453
2026-01-12T09:35:15.7284492Z #6  0xf123372a in mi_arena_try_purge () at /build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/arena.c:1965
2026-01-12T09:35:15.7285668Z #7  0xf1233910 in mi_arenas_try_purge () at /build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/arena.c:2000
2026-01-12T09:35:15.7287027Z #8  0xf123138b in _mi_arenas_collect () at /build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/arena.c:1206
2026-01-12T09:35:15.7288216Z #9  0xf124a9c3 in mi_theap_collect_ex () at /build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/theap.c:134
2026-01-12T09:35:15.7289377Z #10 0xf124aa28 in mi_theap_collect () at /build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/theap.c:145
2026-01-12T09:35:15.7290517Z #11 0xf123c397 in mi_process_done () at /build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/init.c:929
2026-01-12T09:35:15.7291668Z #12 0xf123c473 in _mi_auto_process_done () at /build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/init.c:956
2026-01-12T09:35:15.7293258Z #13 0xf124d124 in mi_process_detach () at /build/cpp/mimalloc_ep-prefix/src/mimalloc_ep/src/prim/prim.c:45
2026-01-12T09:35:15.7294169Z #14 0xf262d12a in ?? () from /lib/ld-linux.so.2
2026-01-12T09:35:15.7294688Z #15 0xf2630991 in ?? () from /lib/ld-linux.so.2
2026-01-12T09:35:15.7295250Z #16 0xee605b66 in ?? () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7296044Z #17 0xee605d81 in exit () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7296684Z #18 0xee5ed2e1 in ?? () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7297366Z #19 0xee5ed398 in __libc_start_main () from /lib/i386-linux-gnu/libc.so.6
2026-01-12T09:35:15.7297989Z #20 0x61726e27 in _start ()
2026-01-12T09:35:15.7298417Z !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[pitrou]

@daanx

[pitrou]

I was unable to reproduce locally with the same Docker setup as on that CI, so I assume there's something specific on GitHub Actions that triggers this.

[pitrou]

That said, this snippet looks fishy :)

mimalloc/src/bitmap.c

Lines 1453 to 1454 in 4dbc66f

	mi_assert_internal(rngslices <= MI_BFIELD_BITS);
	if (rngslices > MI_BFIELD_BITS) { rngslices = MI_BFIELD_BITS; }