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dimaqq/cpython-3.13-gc-crash.gdb

Created June 4, 2025 04:56
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cpython-3.13-gc-crash.gdb
⋊> dima@bb ⋊> ~ coredumpctl debug 3836963 13:51:34
PID: 3836963 (python3)
UID: 1000 (dima)
GID: 1000 (dima)
Signal: 11 (SEGV)
Timestamp: Wed 2025-06-04 07:03:35 JST (6h ago)
Command Line: /code/operator-xdist-3.7/.venv/bin/python3 -u -c $'import sys;exec(eval(sys.stdin.readline()))'
Executable: /home/dima/3.13-dev/python/install/bin/python3.13d
Control Group: /user.slice/user-1000.slice/[email protected]/tmux-spawn-f92e4ddc-4a2d-4bf7-a7e2-58abbd1ec088.scope
Unit: [email protected]
User Unit: tmux-spawn-f92e4ddc-4a2d-4bf7-a7e2-58abbd1ec088.scope
Slice: user-1000.slice
Owner UID: 1000 (dima)
Boot ID: b85c1c88136d4f119393cf603e4f97c1
Machine ID: 4da07f4a71834d0cb0719ae6921e13f7
Hostname: bb
Storage: /var/lib/systemd/coredump/core.python3.1000.b85c1c88136d4f119393cf603e4f97c1.3836963.1748988215000000.zst (present)
Size on Disk: 9.8M
Message: Process 3836963 (python3) of user 1000 dumped core.
Module /home/dima/3.13-dev/python/install/bin/python3.13d without build-id.
Module /home/dima/3.13-dev/python/install/bin/python3.13d
Module libgcc_s.so.1 from deb gcc-14-14.2.0-4ubuntu2~24.04.amd64
Stack trace of thread 3836963:
#0 0x00005e558c221635 n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x3ef635)
#1 0x00005e558c21f0ef n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x3ed0ef)
#2 0x00005e558c257dee n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x425dee)
#3 0x00005e558c256829 n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x424829)
#4 0x00005e558c2a7e74 n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x475e74)
#5 0x00005e558c2a86f1 n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x4766f1)
#6 0x00005e558c2a874c n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x47674c)
#7 0x00007c515762a1ca __libc_start_call_main (libc.so.6 + 0x2a1ca)
#8 0x00007c515762a28b __libc_start_main_impl (libc.so.6 + 0x2a28b)
#9 0x00005e558bfd39d2 n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x1a19d2)
ELF object binary architecture: AMD x86-64
GNU gdb (Ubuntu 15.0.50.20240403-0ubuntu1) 15.0.50.20240403-git
Copyright (C) 2024 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from /home/dima/3.13-dev/python/install/bin/python3.13d...
warning: core file may not match specified executable file.
[New LWP 3836963]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/code/operator-xdist-3.7/.venv/bin/python3 -u -c import sys;exec(eval(sys.stdin'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 gc_get_refs (g=0x99dd7d052835e0c0) at Python/gc.c:71
warning: 71 Python/gc.c: No such file or directory
(gdb) directory ~/cpython
Source directories searched: /home/dima/cpython:$cdir:$cwd
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dimaqq commented Jun 4, 2025 

(gdb) print g
$1 = (PyGC_Head *) 0x99dd7d052835e0c0
(gdb) print g->_gc_prev
Cannot access memory at address 0x99dd7d052835e0c8
(gdb) info proc map
Mapped address spaces:

          Start Addr           End Addr       Size     Offset objfile
      0x5e558be32000     0x5e558bfd0000   0x19e000        0x0 /home/dima/3.13-dev/python/install/bin/python3.13d
      0x5e558bfd0000     0x5e558cd5b000   0xd8b000   0x19e000 /home/dima/3.13-dev/python/install/bin/python3.13d
      0x5e558cd5b000     0x5e558d354000   0x5f9000   0xf29000 /home/dima/3.13-dev/python/install/bin/python3.13d
      0x5e558d354000     0x5e558d454000   0x100000  0x1522000 /home/dima/3.13-dev/python/install/bin/python3.13d
      0x5e558d454000     0x5e558d511000    0xbd000  0x1622000 /home/dima/3.13-dev/python/install/bin/python3.13d
      0x5e558f4ad000     0x5e558f4bc000     0xf000  0x367b000 /home/dima/3.13-dev/python/install/bin/python3.13d
      0x7c5154200000     0x7c5154244000    0x44000        0x0 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/pydantic_core/_pydantic_core.cpython-313-x86_64-linux-gnu.so
      0x7c5154244000     0x7c515454e000   0x30a000    0x44000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/pydantic_core/_pydantic_core.cpython-313-x86_64-linux-gnu.so
      0x7c515454e000     0x7c5154655000   0x107000   0x34e000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/pydantic_core/_pydantic_core.cpython-313-x86_64-linux-gnu.so
      0x7c5154655000     0x7c5154689000    0x34000   0x454000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/pydantic_core/_pydantic_core.cpython-313-x86_64-linux-gnu.so
      0x7c5154689000     0x7c515468e000     0x5000   0x488000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/pydantic_core/_pydantic_core.cpython-313-x86_64-linux-gnu.so
      0x7c515474d000     0x7c5154751000     0x4000        0x0 /usr/lib/x86_64-linux-gnu/libgcc_s.so.1
      0x7c5154751000     0x7c5154775000    0x24000     0x4000 /usr/lib/x86_64-linux-gnu/libgcc_s.so.1
      0x7c5154775000     0x7c5154779000     0x4000    0x28000 /usr/lib/x86_64-linux-gnu/libgcc_s.so.1
      0x7c5154779000     0x7c515477a000     0x1000    0x2b000 /usr/lib/x86_64-linux-gnu/libgcc_s.so.1
      0x7c515477a000     0x7c515477b000     0x1000    0x2c000 /usr/lib/x86_64-linux-gnu/libgcc_s.so.1
      0x7c5155871000     0x7c5155876000     0x5000        0x0 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/yaml/_yaml.cpython-313-x86_64-linux-gnu.so
      0x7c5155876000     0x7c51558bf000    0x49000     0x5000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/yaml/_yaml.cpython-313-x86_64-linux-gnu.so
      0x7c51558bf000     0x7c51558c8000     0x9000    0x4e000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/yaml/_yaml.cpython-313-x86_64-linux-gnu.so
      0x7c51558c8000     0x7c51558c9000     0x1000    0x56000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/yaml/_yaml.cpython-313-x86_64-linux-gnu.so
      0x7c51558c9000     0x7c51558cb000     0x2000    0x57000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/yaml/_yaml.cpython-313-x86_64-linux-gnu.so
      0x7c5156800000     0x7c51575ec000   0xdec000        0x0 /usr/lib/locale/locale-archive
      0x7c51575f2000     0x7c51575f6000     0x4000        0x0 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/wrapt/_wrappers.cpython-313-x86_64-linux-gnu.so
      0x7c51575f6000     0x7c51575fb000     0x5000     0x4000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/wrapt/_wrappers.cpython-313-x86_64-linux-gnu.so
      0x7c51575fb000     0x7c51575fd000     0x2000     0x9000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/wrapt/_wrappers.cpython-313-x86_64-linux-gnu.so
      0x7c51575fd000     0x7c51575fe000     0x1000     0xa000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/wrapt/_wrappers.cpython-313-x86_64-linux-gnu.so
      0x7c51575fe000     0x7c5157600000     0x2000     0xb000 /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/wrapt/_wrappers.cpython-313-x86_64-linux-gnu.so
      0x7c5157600000     0x7c5157628000    0x28000        0x0 /usr/lib/x86_64-linux-gnu/libc.so.6
      0x7c5157628000     0x7c51577b0000   0x188000    0x28000 /usr/lib/x86_64-linux-gnu/libc.so.6
      0x7c51577b0000     0x7c51577ff000    0x4f000   0x1b0000 /usr/lib/x86_64-linux-gnu/libc.so.6
      0x7c51577ff000     0x7c5157803000     0x4000   0x1fe000 /usr/lib/x86_64-linux-gnu/libc.so.6
      0x7c5157803000     0x7c5157805000     0x2000   0x202000 /usr/lib/x86_64-linux-gnu/libc.so.6
      0x7c5157880000     0x7c5157881000     0x1000        0x0 /usr/lib/x86_64-linux-gnu/librt.so.1
      0x7c5157881000     0x7c5157882000     0x1000     0x1000 /usr/lib/x86_64-linux-gnu/librt.so.1
      0x7c5157882000     0x7c5157883000     0x1000     0x2000 /usr/lib/x86_64-linux-gnu/librt.so.1
      0x7c5157883000     0x7c5157884000     0x1000     0x2000 /usr/lib/x86_64-linux-gnu/librt.so.1
      0x7c5157884000     0x7c5157885000     0x1000     0x3000 /usr/lib/x86_64-linux-gnu/librt.so.1
      0x7c5157885000     0x7c5157895000    0x10000        0x0 /usr/lib/x86_64-linux-gnu/libm.so.6
      0x7c5157895000     0x7c5157914000    0x7f000    0x10000 /usr/lib/x86_64-linux-gnu/libm.so.6
      0x7c5157914000     0x7c515796c000    0x58000    0x8f000 /usr/lib/x86_64-linux-gnu/libm.so.6
      0x7c515796c000     0x7c515796d000     0x1000    0xe7000 /usr/lib/x86_64-linux-gnu/libm.so.6
      0x7c515796d000     0x7c515796e000     0x1000    0xe8000 /usr/lib/x86_64-linux-gnu/libm.so.6
      0x7c515796e000     0x7c515796f000     0x1000        0x0 /usr/lib/x86_64-linux-gnu/libutil.so.1
      0x7c515796f000     0x7c5157970000     0x1000     0x1000 /usr/lib/x86_64-linux-gnu/libutil.so.1
      0x7c5157970000     0x7c5157971000     0x1000     0x2000 /usr/lib/x86_64-linux-gnu/libutil.so.1
      0x7c5157971000     0x7c5157972000     0x1000     0x2000 /usr/lib/x86_64-linux-gnu/libutil.so.1
      0x7c5157972000     0x7c5157973000     0x1000     0x3000 /usr/lib/x86_64-linux-gnu/libutil.so.1
      0x7c5157973000     0x7c5157974000     0x1000        0x0 /usr/lib/x86_64-linux-gnu/libdl.so.2
      0x7c5157974000     0x7c5157975000     0x1000     0x1000 /usr/lib/x86_64-linux-gnu/libdl.so.2
      0x7c5157975000     0x7c5157976000     0x1000     0x2000 /usr/lib/x86_64-linux-gnu/libdl.so.2
      0x7c5157976000     0x7c5157977000     0x1000     0x2000 /usr/lib/x86_64-linux-gnu/libdl.so.2
      0x7c5157977000     0x7c5157978000     0x1000     0x3000 /usr/lib/x86_64-linux-gnu/libdl.so.2
      0x7c5157978000     0x7c5157979000     0x1000        0x0 /usr/lib/x86_64-linux-gnu/libpthread.so.0
      0x7c5157979000     0x7c515797a000     0x1000     0x1000 /usr/lib/x86_64-linux-gnu/libpthread.so.0
      0x7c515797a000     0x7c515797b000     0x1000     0x2000 /usr/lib/x86_64-linux-gnu/libpthread.so.0
      0x7c515797b000     0x7c515797c000     0x1000     0x2000 /usr/lib/x86_64-linux-gnu/libpthread.so.0
      0x7c515797c000     0x7c515797d000     0x1000     0x3000 /usr/lib/x86_64-linux-gnu/libpthread.so.0
      0x7c5157984000     0x7c515798b000     0x7000        0x0 /usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache
      0x7c5157993000     0x7c5157994000     0x1000        0x0 /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
      0x7c5157994000     0x7c51579bf000    0x2b000     0x1000 /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
      0x7c51579bf000     0x7c51579c9000     0xa000    0x2c000 /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
      0x7c51579c9000     0x7c51579cb000     0x2000    0x36000 /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
      0x7c51579cb000     0x7c51579cd000     0x2000    0x38000 /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
(gdb) x/1gx 0x99dd7d052835e0c0
0x99dd7d052835e0c0:     Cannot access memory at address 0x99dd7d052835e0c0

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dimaqq commented Jun 4, 2025 

(gdb) frame 1
#1  move_unreachable (young=0x5e558d4e2890 <_PyRuntime+111872>, unreachable=0x7ffc77bd0718) at Python/gc.c:562
562             if (gc_get_refs(gc)) {
(gdb) list
557          * left of us in 'young' now have been scanned, and no objects here
558          * or to the right have been scanned yet.
559          */
560
561         while (gc != young) {
562             if (gc_get_refs(gc)) {
563                 /* gc is definitely reachable from outside the
564                  * original 'young'.  Mark it as such, and traverse
565                  * its pointers to find any other objects that may
566                  * be directly reachable from it.  Note that the
(gdb) print gc
$2 = <optimized out>
(gdb) print unreachable
$3 = (PyGC_Head *) 0x7ffc77bd0718
(gdb) print *unreachable
$4 = {_gc_next = 136688785057025, _gc_prev = 136688674174224}
(gdb) print unreachable->_gc_next
$5 = 136688785057025
(gdb) print *unreachable->_gc_next
$6 = 1364621925
(gdb) printf "%p\n", unreachable->_gc_next
0x7c51567a6501
(gdb) x/1gx unreachable->_gc_next
0x7c51567a6501: 0x1a00007c51567a65
(gdb) print ((PyGC_Head *) unreachable->_gc_next)->_gc_prev
$7 = 720576490075831559
(gdb) :q
Undefined command: "".  Try "help".
(gdb) set $unr = unreachable->_gc_next
(gdb) print offsetof(PyObject_GC, gc.gc_next)
No symbol "offsetof" in current context.
(gdb) ptype PyObject_GC
No symbol "PyObject_GC" in current context.
(gdb) ptype PyGC_Head
type = struct {
    uintptr_t _gc_next;
    uintptr_t _gc_prev;
}
(gdb) info types PyObject_GC
All types matching regular expression "PyObject_GC":
(gdb) set $obj = (PyObject *)((char*)$unr - 16)
(gdb) print *obj
No symbol "obj" in current context.
(gdb) print ((PyObject *)$obj)->ob_type->tp_name
Cannot access memory at address 0x61fdfdfdfdfdfe15
(gdb) print *((PyObject *)$obj)
$8 = {{ob_refcnt = 8018659136533168128, ob_refcnt_split = {0, 1866989568}}, ob_type = 0x61fdfdfdfdfdfdfd}
(gdb) print ((PyGC_Head *)young)->_gc_next
$9 = 136688784392256
(gdb) print *((PyGC_Head *)young)->_gc_next
$10 = 1450197136
(gdb) info sharedlibrary
From                To                  Syms Read   Shared Object Library
0x00007c5157979040  0x00007c5157979105  Yes         /lib/x86_64-linux-gnu/libpthread.so.0
0x00007c5157974040  0x00007c5157974105  Yes         /lib/x86_64-linux-gnu/libdl.so.2
0x00007c515796f040  0x00007c515796f105  Yes         /lib/x86_64-linux-gnu/libutil.so.1
0x00007c5157895420  0x00007c51579133a6  Yes         /lib/x86_64-linux-gnu/libm.so.6
0x00007c5157881080  0x00007c51578812b1  Yes         /lib/x86_64-linux-gnu/librt.so.1
0x00007c5157628800  0x00007c51577afcb9  Yes         /lib/x86_64-linux-gnu/libc.so.6
0x00007c5157994000  0x00007c51579be195  Yes         /lib64/ld-linux-x86-64.so.2
0x00007c5155876aa0  0x00007c51558be167  Yes         /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/yaml/_yaml.cpython-313-x86_64-linux-gnu.so
0x00007c51575f65b0  0x00007c51575fadcd  Yes         /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/wrapt/_wrappers.cpython-313-x86_64-linux-gnu.so
0x00007c5154244090  0x00007c515454d8bf  Yes (*)     /code/operator-xdist-3.7/.venv/lib/python3.13/site-packages/pydantic_core/_pydantic_core.cpython-313-x86_64-linux-gnu.so
0x00007c5154751780  0x00007c5154774745  Yes (*)     /lib/x86_64-linux-gnu/libgcc_s.so.1
(*): Shared library is missing debugging information.

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dimaqq commented Jun 4, 2025

Journal entries:

Jun 04 07:03:35 bb kernel: traps: python3[3836963] general protection fault ip:5e558c221635 sp:7ffc77bd0620 error:0 in python3.13d[3ef635,5e558bfd0000+d8b000]

...


Jun 04 07:03:36 bb (sd-parse-elf)[3844445]: Could not parse number of program headers from core file: invalid `Elf' handle
Jun 04 07:03:36 bb systemd-coredump[3844354]: Process 3836963 (python3) of user 1000 dumped core.

                                              Module /home/dima/3.13-dev/python/install/bin/python3.13d without build-id.
                                              Module /home/dima/3.13-dev/python/install/bin/python3.13d
                                              Module libgcc_s.so.1 from deb gcc-14-14.2.0-4ubuntu2~24.04.amd64
                                              Stack trace of thread 3836963:
                                              #0  0x00005e558c221635 n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x3ef635)
                                              #1  0x00005e558c21f0ef n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x3ed0ef)
                                              #2  0x00005e558c257dee n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x425dee)
                                              #3  0x00005e558c256829 n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x424829)
                                              #4  0x00005e558c2a7e74 n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x475e74)
                                              #5  0x00005e558c2a86f1 n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x4766f1)
                                              #6  0x00005e558c2a874c n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x47674c)
                                              #7  0x00007c515762a1ca __libc_start_call_main (libc.so.6 + 0x2a1ca)
                                              #8  0x00007c515762a28b __libc_start_main_impl (libc.so.6 + 0x2a28b)
                                              #9  0x00005e558bfd39d2 n/a (/home/dima/3.13-dev/python/install/bin/python3.13d + 0x1a19d2)
                                              ELF object binary architecture: AMD x86-64
Jun 04 07:03:36 bb systemd[1]: [email protected]: Deactivated successfully.
Jun 04 07:03:36 bb systemd[1]: [email protected]: Triggering OnSuccess= dependencies.
Jun 04 07:03:36 bb systemd[1]: Starting [email protected]...

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