Public issue detail

Runaway CPU investigation for llama-server: unknown userspace loop at mtree_load

llama-server is stuck in a likely unclassified userspace loop: 14.70% of sampled CPU passed through mtree_load, with repeated thread backtraces show 22 thread(s) around 0x00007f6833ca74be in sem_trywait () from target:<path> and 1 thread(s) around 0x00007f6833ca74be in sem_trywait () from target:<path>.

highscore: 106reports: 1

Last seen: 2026-07-10 02:05 UTC. Public JSON: /v1/issues/019f41b3-1a9c-7602-aff9-39b83150de15

Technical snapshot

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

Representative thread backtrace

  • Command: /usr/local/lib/ollama/llama-server --model /usr/share/ollama/.ollama/models/blobs/sha256-797b70c4edf85907fe0a49eb85811256f65fa0f7bf52166b147fd16be2be4662 --port 38617 --host 127.0.0.1 --no-webui --offline -c 512 -np 1 --log-verbosity 4 --no-log-prefix --no-log-timestamps --flash-attn auto --embedding -b 512 -ub 512 -t 8 --context-shift --keep 4
  • 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.
  • Thread summary: thread backtraces show 22 thread(s) around 0x00007f6833ca74be in sem_trywait () from target:<path> and 1 thread(s) around 0x00007f6833ca74be in sem_trywait () from target:<path>
  • Contention signals: gdb-stderr: gdb: warning: Couldn't determine a path for the index cache directory.
  • Repeated loop: futex -> futex -> futex
  • Top syscalls: futex x1221, <... futex resumed>) = -1 ETIMEDOUT x193, close x25, openat x25
  • Kernel: 6.17.10+deb14-amd64
  • Distribution: debian
0x00007f6833ca74be in sem_trywait () from target:<path>
0x00007f6833c9bc84 in __libc_alloca_cutoff () from target:<path>
0x00007f6833c9c29c in __nptl_death_event () from target:<path>
0x00007f6833c9e828 in pthread_cond_wait () from target:<path>
0x00007f6833ebaaa7 in std::condition_variable::wait(std::unique_lock<std::mutex>&) () from target:<path>++.so.6
0x00007f683485c90b in std::thread::_State_impl<std::thread::_Invoker<std::tuple<common_log::resume()::{lambda()#1}> > >::_M_run() () from target:<path>
0x00007f6833eec446 in std::error_code::default_error_condition() const () from target:<path>++.so.6
0x00007f6833c9f289 in pthread_condattr_setpshared () from target:<path>

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.

llama-server is stuck in a likely unclassified userspace loop: 14.88% of sampled CPU passed through mt_find, with repeated thread backtraces show 22 thread(s) around 0x00007fe6800a74be in sem_trywait () from target:<path> and 1 thread(s) around 0x00007fe6800a74be in sem_trywait () from target:<path>.

highscore: 106reports: 1similarity: 99%

Why this looks related: same classification, same subsystem, same target, same wait site, very similar public summary

Last seen: 2026-07-10 04:19 UTC. Public page: /issues/019f427c-2154-77c0-818c-eded7911a06a. Public JSON: /v1/issues/019f427c-2154-77c0-818c-eded7911a06a

llama-server is stuck in a likely unclassified userspace loop: 10.95% of sampled CPU passed through num_to_str, with repeated thread backtraces show 22 thread(s) around 0x00007f942aaa74be in ?? () from target:<path> and 1 thread(s) around 0x00007f942aaa74be in ?? () from target:<path>.

highscore: 106reports: 1similarity: 99%

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

Last seen: 2026-07-08 20:41 UTC. Public page: /issues/019f4355-227b-7972-b32b-3ce63462b54c. Public JSON: /v1/issues/019f4355-227b-7972-b32b-3ce63462b54c

ollama is stuck in a likely unclassified userspace loop: 33.33% of sampled CPU passed through __get_user_8, with repeated thread backtraces show 1 thread(s) around 0x000055c5c39ed143 in ?? () and 1 thread(s) around 0x000055c5c39ed143 in ?? ().

highscore: 106reports: 1successful triagesimilarity: 87%

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

Last seen: 2026-06-30 14:02 UTC. Public page: /issues/019da1fb-dcb3-72b1-ba41-1fd6b172a97c. Public JSON: /v1/issues/019da1fb-dcb3-72b1-ba41-1fd6b172a97c

ollama is stuck in a likely unclassified userspace loop: 33.33% of sampled CPU passed through fdget, with repeated thread backtraces show 1 thread(s) around 0x000055c5c39ed143 in ?? () and 1 thread(s) around 0x000055c5c39ed143 in ?? ().

highscore: 106reports: 1successful triagesimilarity: 87%

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

Last seen: 2026-07-07 14:12 UTC. Public page: /issues/019dbcec-f056-7ae0-bc8f-d6d03bb07fcc. Public JSON: /v1/issues/019dbcec-f056-7ae0-bc8f-d6d03bb07fcc

ollama is stuck in a likely unclassified userspace loop: 26.50% of sampled CPU passed through fput, with repeated thread backtraces show 1 thread(s) around 0x000055c5c39ed143 in ?? () and 1 thread(s) around 0x000055c5c39ed143 in ?? ().

highscore: 106reports: 1successful triagesimilarity: 87%

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

Last seen: 2026-07-06 09:10 UTC. Public page: /issues/019dbb1d-f3d1-79d0-be89-356d1cb05fde. Public JSON: /v1/issues/019dbb1d-f3d1-79d0-be89-356d1cb05fde

ollama is stuck in a likely unclassified userspace loop: 25.00% of sampled CPU passed through __pollwait, with repeated thread backtraces show 1 thread(s) around 0x000055c5c39ed143 in ?? () and 1 thread(s) around 0x000055c5c39ed143 in ?? ().

highscore: 106reports: 1successful triagesimilarity: 86%

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

Last seen: 2026-07-06 02:01 UTC. Public page: /issues/019dd09e-61b4-7ed0-a93f-a3480ebc9b11. Public JSON: /v1/issues/019dd09e-61b4-7ed0-a93f-a3480ebc9b11

Published attempts

No public attempts have been published for this issue yet.