Public issue detail

Runaway CPU investigation for sshd-auth: busy poll at default_wake_function

sshd-auth is stuck in a likely busy poll loop: 50.00% of sampled CPU passed through default_wake_function, with repeated read x3, write x2, clock_nanosleep x1.

highpackage: openssh-serversource: opensshscore: 106reports: 1

Last seen: 2026-06-10 01:46 UTC. Public JSON: /v1/issues/019eacc4-cbcf-7c52-be3d-4fd249ca28e9

Technical snapshot

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

Representative thread backtrace

  • Command: sshd-auth: root [net]
  • 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.
  • Wait site: unix_stream_read_generic
  • Hot path: default_wake_function (50.00% sampled CPU)
  • Repeated loop: clock_nanosleep -> write -> ppoll
  • Top syscalls: read x3, write x2, clock_nanosleep x1, exit_group x1
  • Package: openssh-server 1:10.3p1-1
  • Kernel: 6.17.10+deb14-amd64
  • Distribution: debian
unix_stream_read_generic
unix_stream_recvmsg
sock_recvmsg
sock_read_iter
vfs_read
ksys_read
do_syscall_64
entry_SYSCALL_64_after_hwframe

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 sshd-auth: busy poll at unresolved offset in sshd-auth

possible duplicate

sshd-auth is stuck in a likely busy poll loop: 100.00% of sampled CPU passed through unresolved offset, with repeated read x3, write x2, clock_nanosleep x1.

highpackage: openssh-serversource: opensshscore: 106reports: 2patch attempt readysimilarity: 99%

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

Last seen: 2026-06-10 02:14 UTC. Public page: /issues/019e1519-78c6-7813-bebb-aeb6177e1897. Public JSON: /v1/issues/019e1519-78c6-7813-bebb-aeb6177e1897

Runaway CPU investigation for sshd-auth: busy poll at syscall_return_via_sysret

possible duplicate

sshd-auth is stuck in a likely busy poll loop: 50.00% of sampled CPU passed through syscall_return_via_sysret, with repeated read x3, write x2, clock_nanosleep x1.

highpackage: openssh-serversource: opensshscore: 106reports: 2similarity: 99%

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

Last seen: 2026-06-05 16:57 UTC. Public page: /issues/019e3ec4-e457-7410-8e2a-b04690dc6937. Public JSON: /v1/issues/019e3ec4-e457-7410-8e2a-b04690dc6937

Runaway CPU investigation for sshd-auth: timer churn at vfs_write

possible duplicate

sshd-auth is stuck in a likely timer churn loop: 100.00% of sampled CPU passed through vfs_write, with repeated thread backtraces show 1 thread(s) around 0x00007f76d5c9a7d2 in ?? () from target:<path>.

highpackage: openssh-serversource: opensshscore: 106reports: 2patch attempt readysimilarity: 79%

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

Last seen: 2026-06-10 02:14 UTC. Public page: /issues/019e2c59-6707-7471-b7b2-5329d3cdd34e. Public JSON: /v1/issues/019e2c59-6707-7471-b7b2-5329d3cdd34e

Runaway CPU investigation for sshd-auth: timer churn at dequeue_task

possible duplicate

sshd-auth is stuck in a likely timer churn loop: 100.00% of sampled CPU passed through dequeue_task, with repeated thread backtraces show 1 thread(s) around 0x00007f82a4e9a7d2 in ?? () from target:<path>.

highpackage: openssh-serversource: opensshscore: 106reports: 1similarity: 79%

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

Last seen: 2026-06-03 09:04 UTC. Public page: /issues/019e8726-103f-7172-92ea-ca7fe9e367cf. Public JSON: /v1/issues/019e8726-103f-7172-92ea-ca7fe9e367cf

Runaway CPU investigation for sshd-auth: timer churn at tcp_push

possible duplicate

sshd-auth is stuck in a likely timer churn loop: 100.00% of sampled CPU passed through tcp_push, with repeated thread backtraces show 1 thread(s) around 0x00007f51dfe9a7d2 in ?? () from target:<path>.

highpackage: openssh-serversource: opensshscore: 106reports: 1similarity: 78%

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

Last seen: 2026-06-08 19:13 UTC. Public page: /issues/019ea31a-f962-7293-a0ce-bff12d2d13fa. Public JSON: /v1/issues/019ea31a-f962-7293-a0ce-bff12d2d13fa

Runaway CPU investigation for sshd-auth: timer churn at __schedule

possible duplicate

sshd-auth is stuck in a likely timer churn loop: 36.29% of sampled CPU passed through __schedule, with repeated thread backtraces show 1 thread(s) around 0x00007fac7249a7d2 in ?? () from target:<path>.

highpackage: openssh-serversource: opensshscore: 106reports: 1similarity: 77%

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

Last seen: 2026-06-08 23:10 UTC. Public page: /issues/019ea8c5-24b9-7863-b730-83081994767c. Public JSON: /v1/issues/019ea8c5-24b9-7863-b730-83081994767c

Published attempts

No public attempts have been published for this issue yet.

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