Public issue detail

Runaway CPU investigation for python3.13: unknown userspace loop at _PyEval_EvalFrameDefault

python3.13 is stuck in a likely unclassified userspace loop: 22.73% of sampled CPU passed through _PyEval_EvalFrameDefault, with repeated no dominant syscall sample was captured.

highpackage: python3.13-minimalsource: python3.13score: 106reports: 2

Last seen: 2026-05-02 00:35 UTC. Public JSON: /v1/issues/019d3a01-5de6-7581-9470-f0e29db1b7e8

Technical snapshot

This is the clearest retained userspace thread cluster Fixer captured while the process was spinning.

Representative thread backtrace

Why Fixer classified it this way: The process is demonstrably CPU-hot, but the current syscall and symbol sample does not point to a single dominant loop family yet.
Hot path: _PyEval_EvalFrameDefault (22.73% sampled CPU)
Package: python3.13-minimal 3.13.12-1
Kernel: 6.17.10+deb14-amd64
Distribution: debian

Possible duplicates

These are suggestions based on sanitized trigram similarity plus structured fields like package, subsystem, classification, and wait site. They are not auto-merged.

Runaway CPU investigation for python3.13: busy poll at idle_cpu

possible duplicate

python3.13 is stuck in a likely busy poll loop: 40.65% of sampled CPU passed through idle_cpu, with repeated thread backtraces show 1 thread(s) around 0x00007f1c6e7efe92 in pthread_attr_destroy () from target:<path>.

highpackage: python3.13-minimalsource: python3.13score: 106reports: 2similarity: 66%

Why this looks related: same package, same source package, same subsystem, same target

Last seen: 2026-05-19 02:35 UTC. Public page: /issues/019dfead-0293-7062-b24e-c9b04c2f1edb. Public JSON: /v1/issues/019dfead-0293-7062-b24e-c9b04c2f1edb

Runaway CPU investigation for python3.13: busy poll at read_tsc

possible duplicate

python3.13 is stuck in a likely busy poll loop: 50.00% of sampled CPU passed through read_tsc, with repeated thread backtraces show 1 thread(s) around 0x00007f1c6e7efe92 in pthread_attr_destroy () from target:<path>.

highpackage: python3.13-minimalsource: python3.13score: 106reports: 2similarity: 65%

Why this looks related: same package, same source package, same subsystem, same target

Last seen: 2026-05-19 01:01 UTC. Public page: /issues/019da8df-cd0c-7880-ab1e-6dd908d64437. Public JSON: /v1/issues/019da8df-cd0c-7880-ab1e-6dd908d64437

Runaway CPU investigation for python3.13: busy poll at PyObject_GC_Del

possible duplicate

python3.13 is stuck in a likely busy poll loop: 100.00% of sampled CPU passed through PyObject_GC_Del, with repeated thread backtraces show 1 thread(s) around 0x00007f1c6e7efe92 in pthread_attr_destroy () from target:<path>.

highpackage: python3.13-minimalsource: python3.13score: 106reports: 2patch attempt readysimilarity: 64%

Why this looks related: same package, same source package, same subsystem, same target

Last seen: 2026-05-15 03:34 UTC. Public page: /issues/019dd1e0-1f56-7862-9fd2-d20d576df8c4. Public JSON: /v1/issues/019dd1e0-1f56-7862-9fd2-d20d576df8c4

Runaway CPU investigation for python3.13: busy poll at unresolved offset in python3.13

possible duplicate

python3.13 is stuck in a likely busy poll loop: 100.00% of sampled CPU passed through unresolved offset, with repeated thread backtraces show 1 thread(s) around 0x00007f1c6e7efe92 in pthread_attr_destroy () from target:<path>.

highpackage: python3.13-minimalsource: python3.13score: 106reports: 2similarity: 63%

Why this looks related: same package, same source package, same subsystem, same target

Last seen: 2026-05-19 01:48 UTC. Public page: /issues/019dc2a0-9ae7-7f42-8f59-415fe22abe51. Public JSON: /v1/issues/019dc2a0-9ae7-7f42-8f59-415fe22abe51

Runaway CPU investigation for python3.13: busy poll at PyUnicode_FromWideChar

possible duplicate

python3.13 is stuck in a likely busy poll loop: 100.00% of sampled CPU passed through PyUnicode_FromWideChar, with repeated thread backtraces show 1 thread(s) around 0x00007f1c6e7efe92 in pthread_attr_destroy () from target:<path>.

highpackage: python3.13-minimalsource: python3.13score: 106reports: 2patch attempt readysimilarity: 63%

Why this looks related: same package, same source package, same subsystem, same target

Last seen: 2026-05-13 02:59 UTC. Public page: /issues/019e176a-65b7-7d92-a20c-8c276f7ca31a. Public JSON: /v1/issues/019e176a-65b7-7d92-a20c-8c276f7ca31a

Runaway CPU investigation for python3.13: busy poll at unresolved offset in apt_pkg.cpython-313-x86_64-linux-gnu.so

possible duplicate

python3.13 is stuck in a likely busy poll loop: 20.18% of sampled CPU passed through unresolved offset, with repeated thread backtraces show 2 thread(s) around 0x00007fa97251bffe in ?? () from target:<path> and 1 thread(s) around 0x00007fa970081594 in ?? () from target:<path>.

highpackage: python3.13-minimalsource: python3.13score: 106reports: 2successful triagesimilarity: 60%

Why this looks related: same package, same source package, same subsystem, same target

Last seen: 2026-05-19 03:16 UTC. Public page: /issues/019dd98b-0e1d-76e3-9171-f0f72c689536. Public JSON: /v1/issues/019dd98b-0e1d-76e3-9171-f0f72c689536

Worker outcome summary

This issue has 1 recorded worker attempt. Only ready diffs and ready triage handoffs get dedicated public boards. Diagnosis-only reports and blocked attempts are summarized here so it is easier to see why work stalled.

1 failed patch attempts

No ready patch attempts, ready triage handoffs, diagnosis-only reports, explained impossible attempts, or other attempt states.

Most common blockers

patch proposal did not complete cleanly (1 attempt)

Published attempts

failed patch attempt

patch

python3.13 likely remains stuck in an unclassified userspace loop. The diagnosis was captured, but the patch proposal did not complete cleanly.

state: failedcreated: 2026-03-29 14:39 UTCvalidation: failed

Why it stopped

patch proposal did not complete cleanly

Collected context

This older failed attempt predates structured patch failure capture, so Fixer only retained the diagnosis and workspace context.
Subsystem: runaway-process
Diagnosis family: unknown-userspace-loop
Hot path: __strcmp_avx2
Source package: glibc
Workspace source: debian-source
Workspace acquisition: Fetched Debian source package via apt-get source.
Homepage: https://www.gnu.org/software/libc/libc.html

The process is demonstrably CPU-hot, but the current syscall and symbol sample does not point to a single dominant loop family yet.