Bug #1029

Bug #1031: Cannot create buffers of size 4 GiB or greater

lttng load handles out-of-memory badly

Added by Daniel U. Thibault almost 4 years ago. Updated over 3 years ago.

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(LTTng 2.8.0 lttng-tools a0f518a on Ubuntu 14.04.4, kernel 4.2.0-27-generic)

If you lttng load a session that requires too much memory for its buffers (e.g. the sub-buffers' total memory equals or exceeds the (virtual) machine's entire memory capacity), the system reboots (the session loaded was configured to run right away with one kernel channel). One would instead expect LTTng to report the memory allocation failure (followed by the release of any memory already allocated to the session being constructed).


Updated by Jérémie Galarneau almost 4 years ago

  • Priority changed from Normal to High

I was able to reproduce it here. We're looking into it.

Thanks for reporting!


Updated by Jérémie Galarneau almost 4 years ago

To add some more information, this is reproducible using the "enable-channel" command. It is not related to the load command specifically.

Also, my machine does not reboot. The session daemon hangs and I get a backtrace in dmesg.
What I find weird is that the session daemon becomes unkillable (kill -9) which points to something fishy going on.

What size of buffers do you use and what is the machine's configuration?


Updated by Jérémie Galarneau almost 4 years ago

  • Parent task set to #1031

Updated by Jérémie Galarneau over 3 years ago

  • Status changed from New to Resolved

See #1031.

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