Public issue detail

Runaway CPU investigation for smtpd: busy poll at unix_maybe_add_creds

smtpd is stuck in a likely busy poll loop: 14.11% of sampled CPU passed through unix_maybe_add_creds, with repeated thread backtraces show 1 thread(s) around 0x00007f529799e7d2 in ?? () from target:<path>.

highpackage: postfixsource: postfixscore: 106reports: 1

Last seen: 2026-07-04 06:14 UTC. Public JSON: /v1/issues/019ec5c3-2f99-7ea0-9bcc-7718d776a285

Technical snapshot

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

Representative thread backtrace

Command: smtpd -n smtp -t inet -u -c -o stress= -s 2
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 0x00007f529799e7d2 in ?? () from target:<path>
Contention signals: event-loop-wakeups, gdb-stderr: gdb: warning: Couldn't determine a path for the index cache directory. Error while mapping shared library sections: Could not open `target:<path>' as an executable file: Input<path> error Error while mapping shared library sections: Could not open `target:<path>' as an executable file: Input<path> error Error while mapping shared library sections: Could not open `target:<path>' as an executable file: Input<path> error
Repeated loop: alarm -> flock -> alarm
Top syscalls: alarm x4, epoll_wait x2, flock x2, close x1
Package: postfix 3.10.6-1
Kernel: 6.17.10+deb14-amd64
Distribution: debian

0x00007f529799e7d2 in ?? () from target:<path>
0x00007f529799e7ed in ?? () from target:<path>
0x00007f5297a210cd in epoll_wait () from target:<path>
0x00007f5297b58a86 in event_loop () from target:<path>
0x00007f5297c066bf in single_server_main () from target:<path>
0x0000557b99eec24c in ?? ()
0x00007f5297935f77 in ?? () from target:<path>
0x00007f5297936027 in __libc_start_main () 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.

Runaway CPU investigation for smtpd: unknown userspace loop at __memcg_slab_post_alloc_hook

possible duplicate

smtpd is stuck in a likely unclassified userspace loop: 21.02% of sampled CPU passed through __memcg_slab_post_alloc_hook, with repeated thread backtraces show 1 thread(s) around 0x00007f059d1bc7d2 in ?? () from target:<path>.

highpackage: postfixsource: postfixscore: 106reports: 2patch attempt readysimilarity: 73%

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

Last seen: 2026-07-11 04:04 UTC. Public page: /issues/019e23ec-83a0-7823-9092-6f1fcbeea250. Public JSON: /v1/issues/019e23ec-83a0-7823-9092-6f1fcbeea250

Runaway CPU investigation for redis-check-rdb: busy poll at update_curr

possible duplicate

redis-check-rdb is stuck in a likely busy poll loop: 4.80% of sampled CPU passed through update_curr, with repeated thread backtraces show 1 thread(s) around 0x00007f89688a74be in ?? () and 1 thread(s) around 0x00007f89688a74be in ?? ().

highpackage: redis-toolssource: redisscore: 106reports: 1similarity: 69%

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

Last seen: 2026-07-07 12:41 UTC. Public page: /issues/019f3c77-d8db-79f2-96d6-1595084d836f. Public JSON: /v1/issues/019f3c77-d8db-79f2-96d6-1595084d836f

Runaway CPU investigation for redis-check-rdb: busy poll at unresolved offset in libc.so.6

possible duplicate

redis-check-rdb is stuck in a likely busy poll loop: 6.51% of sampled CPU passed through unresolved offset, with repeated thread backtraces show 1 thread(s) around 0x00007f89688a74be in ?? () and 1 thread(s) around 0x00007f89688a74be in ?? ().

highpackage: redis-toolssource: redisscore: 106reports: 2patch attempt readysimilarity: 66%

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

Last seen: 2026-07-09 13:37 UTC. Public page: /issues/019ddbca-7201-7d22-ba77-0c6c084821ee. Public JSON: /v1/issues/019ddbca-7201-7d22-ba77-0c6c084821ee

Runaway CPU investigation for redis-check-rdb: busy poll at parse_printf_format

possible duplicate

redis-check-rdb is stuck in a likely busy poll loop: 4.69% of sampled CPU passed through parse_printf_format, with repeated thread backtraces show 1 thread(s) around 0x00007f89688a74be in sem_trywait () and 1 thread(s) around 0x00007f89688a74be in sem_trywait ().

highpackage: redis-toolssource: redisscore: 106reports: 1similarity: 65%

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

Last seen: 2026-07-10 05:14 UTC. Public page: /issues/019f4a40-a0c0-7f03-8b78-14eb542d96f6. Public JSON: /v1/issues/019f4a40-a0c0-7f03-8b78-14eb542d96f6

Runaway CPU investigation for redis-check-rdb: busy poll at _dl_mcount_wrapper

possible duplicate

redis-check-rdb is stuck in a likely busy poll loop: 4.54% of sampled CPU passed through _dl_mcount_wrapper, with repeated thread backtraces show 1 thread(s) around 0x00007f89688a74be in sem_trywait () and 1 thread(s) around 0x00007f89688a74be in sem_trywait ().

highpackage: redis-toolssource: redisscore: 106reports: 1similarity: 65%

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

Last seen: 2026-07-11 03:38 UTC. Public page: /issues/019f4885-4b06-73b1-b87b-845532d67d90. Public JSON: /v1/issues/019f4885-4b06-73b1-b87b-845532d67d90

Runaway CPU investigation for redis-check-rdb: busy poll at pthread_mutex_trylock

possible duplicate

redis-check-rdb is stuck in a likely busy poll loop: 7.13% of sampled CPU passed through pthread_mutex_trylock, with repeated thread backtraces show 1 thread(s) around 0x00007f89688a74be in sem_trywait () and 1 thread(s) around 0x00007f89688a74be in sem_trywait ().

highpackage: redis-toolssource: redisscore: 106reports: 1similarity: 65%

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

Last seen: 2026-07-11 01:37 UTC. Public page: /issues/019dd9db-4401-7352-a385-3fee52f27d28. Public JSON: /v1/issues/019dd9db-4401-7352-a385-3fee52f27d28

Published attempts

No public attempts have been published for this issue yet.