#1148883 liblttng-ust1t64: Big memory usage when RLIMIT_NOFILE is high

Package:
liblttng-ust1t64
Source:
liblttng-ust1t64
Description:
LTTng 2.0 Userspace Tracer (tracing libraries)
Submitter:
MOESSBAUER, Felix
Date:
2026-09-24 16:53:01 UTC
Severity:
normal
#1148883#5
Date:
2026-09-24 16:50:30 UTC
From:
To:
Dear Maintainer,

when using LTTng-UST in a trixie container, the RLIMIT_NOFILE is
extremely high (1073741816), which results in 128 MB of RSS memory that
is mapped into each process that links liblttng-ust1t64. Note, that
this effect is independent of a running tracing session.

This already has been reported upstream [1] and a fix is available as
well. I backported the fix to 2.13.9-1 (attached). Please consider
creating a new stable release, as this behavior is definitely
unexpected and in many case breaks the container memory limits.

[1] https://bugs.lttng.org/issues/1438

Best regards,
Felix Moessbauer

Siemens AG
Linux Expert Center
Friedrich-Ludwig-Bauer-Str. 3
85748 Garching, Germany