Public issue detail

Runaway CPU investigation for perl: busy poll at wakeup_preempt

perl is stuck in a likely busy poll loop: 50.00% of sampled CPU passed through wakeup_preempt, with repeated thread backtraces show 1 thread(s) around __internal_syscall_cancel (a1=..., a2=..., a3=..., a4=..., a5=..., a6=..., nr=...) at .<path>:44.

highpackage: perl-basesource: perlscore: 106reports: 1

Last seen: 2026-10-24 08:15 UTC. Public JSON: /v1/issues/01a16cfa-9730-72e0-bcbd-c54d60d21608

Technical snapshot

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

Representative thread backtrace

  • Command: /usr/bin/perl -wT /usr/sbin/munin-node --foreground
  • Why Fixer classified it this way: The trace repeatedly returns to a poll-family syscall without meaningful blocking, which suggests a busy event-loop wakeup.
  • Thread summary: thread backtraces show 1 thread(s) around __internal_syscall_cancel (a1=..., a2=..., a3=..., a4=..., a5=..., a6=..., nr=...) at .<path>:44
  • Contention signals: gdb-stderr: gdb: warning: Couldn't determine a path for the index cache directory. warning: 44 .<path>: No such file or directory
  • Repeated loop: pselect6 -> pselect6 -> pselect6
  • Top syscalls: pselect6 x3
  • Package: perl-base 5.42.3-1
  • Kernel: 7.1.8+deb14.1-amd64
  • Distribution: debian
__internal_syscall_cancel (a1=..., a2=..., a3=..., a4=..., a5=..., a6=..., nr=...) at .<path>:44
0x00007ffb46c1ba1d in __syscall_cancel (a1=..., a2=..., a3=..., a4=..., a5=..., a6=..., nr=...) at .<path>:75
0x00007ffb46c9a8af in __GI___select (nfds=..., readfds=..., writefds=..., exceptfds=..., timeout=...) at ..<path>:69
0x000055755d1b546c in Perl_sortsv ()
0x000055755d21afa6 in Perl_runops_standard ()
0x000055755d0f3f85 in perl_run ()
0x000055755d0c46ae in main ()

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 perl: busy poll at perf_ctx_enable

possible duplicate

perl is stuck in a likely busy poll loop: 100.00% of sampled CPU passed through perf_ctx_enable, with repeated thread backtraces show 1 thread(s) around 0x00007f82eb9e87d2 in ?? () from target:<path>.

highpackage: perl-basesource: perlscore: 106reports: 2successful triagesimilarity: 99%

Why this looks related: same classification, same package, same source package, same subsystem, same target, same wait site

Last seen: 2026-10-24 03:30 UTC. Public page: /issues/019e4743-6f51-7fc1-b372-9900d37706a1. Public JSON: /v1/issues/019e4743-6f51-7fc1-b372-9900d37706a1

Runaway CPU investigation for postgres: busy poll at sqlite3VdbeExec

possible duplicate

postgres is stuck in a likely busy poll loop: 9.57% of sampled CPU passed through sqlite3VdbeExec, with repeated thread backtraces show 1 thread(s) around 0x00007f3dd70ac60d in select () from target:<path>.

highscore: 106reports: 1similarity: 71%

Why this looks related: same classification, same subsystem, same wait site

Last seen: 2026-10-02 18:03 UTC. Public page: /issues/019f9de5-ae93-70a0-b43c-cc5fcfe33721. Public JSON: /v1/issues/019f9de5-ae93-70a0-b43c-cc5fcfe33721

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: 2successful triagesimilarity: 70%

Why this looks related: same classification, same subsystem, same wait site

Last seen: 2026-10-10 01:56 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 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: 2successful triagesimilarity: 69%

Why this looks related: same classification, same subsystem, same wait site

Last seen: 2026-10-04 02:36 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 _PyEval_FrameClearAndPop

possible duplicate

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

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

Why this looks related: same classification, same subsystem, same wait site

Last seen: 2026-10-25 06:03 UTC. Public page: /issues/019dd062-04a8-7e03-b3a3-5bb273aa2f42. Public JSON: /v1/issues/019dd062-04a8-7e03-b3a3-5bb273aa2f42

Runaway CPU investigation for postgres: file not found retry at pglz_decompress

possible duplicate

postgres is stuck in a likely file not found retry loop: 3.77% of sampled CPU passed through pglz_decompress, with repeated thread backtraces show 1 thread(s) around 0x00007f92e0a4e687 in __GI__IO_flush_all () from target:<path>.

highscore: 106reports: 1similarity: 48%

Why this looks related: same subsystem, same wait site

Last seen: 2026-10-13 05:43 UTC. Public page: /issues/019fa653-58fc-7d62-b84f-1f51afcbf926. Public JSON: /v1/issues/019fa653-58fc-7d62-b84f-1f51afcbf926

Published attempts

No public attempts have been published for this issue yet.

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