Bug 41754

Summary:	conf_pulse_hook_load_if_running allocates shm at a dangerous time
Product:	PulseAudio	Reporter:	Paul Davis <paul>
Component:	alsa	Assignee:	pulseaudio-bugs
Status:	RESOLVED MOVED	QA Contact:	pulseaudio-bugs
Severity:	normal
Priority:	medium	CC:	lennart
Version:	unspecified
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Paul Davis 2011-10-13 10:24:15 UTC

if JACK is started in its default real-time mode (with memlockall in effect), it will trigger a call to the libasound function  snd_config_search_definition(). This will eventually result in a call to conf_pulse_hook_load_if_running() within libasound_module_conf_pulse.so, which will in turn eventually call  pa_shm_create_rw(), which allocates 64MB of shared memory. JACK's RT mode forces this to be pinned into physical RAM, which on a "small memory" system (e.g. 700MB with Ubuntu 10.10 (32 bit system) will cause JACK to bus error and the overall system to behave very erratically from a user perspective due to OOM-like conditions.

it does not seem appropriate for PA to be allocating shm in response to libasound checking device definitions.

Comment 1 Paul Davis 2011-10-13 10:25:09 UTC

(minor error in report: the system on which this was observed is a 64 bit install, thus making the 770MB of RAM even more limited).

Comment 2 Paul Davis 2011-10-13 10:55:03 UTC

c.f. https://bugs.launchpad.net/ubuntu/+source/jack-audio-connection-kit/+bug/491329

Comment 3 Paul Davis 2011-10-13 10:56:20 UTC

c.f. http://pulseaudio.org/ticket/806

Comment 4 GitLab Migration User 2018-07-30 10:21:07 UTC

-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

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