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Bug #687
closedCrashing lttng-sessiond with enable-event --function
Start date:
11/19/2013
Due date:
% Done:
0%
Estimated time:
Description
I managed to crash lttng-sessiond while fooling around with kretprobe events.
First I stopped the lttng-sessiond service and started a verbose root session manager to try and get the crash log (attached).
Then I did this:
$ lttng create krpso Session krpso created. Traces will be written in /home/daniel/lttng-traces/krpso-20131119-095940 $ lttng enable-event -k krpso --function sys_open kernel event krpso created in channel channel0
Having previously run the above tracing session and obtained this babeltrace:
timestamp = 09:53:54.443925388, delta = +?.?????????, trace = /home/daniel/lttng-traces/krpso-20131119-095319/kernel, trace:hostname = sds-dut-vb, trace:domain = kernel, name = krpso_entry, stream.packet.context = { cpu_id = 0 }, event.fields = { ip = 0xFFFFFFFF81176A70, parent_ip = 0xFFFFFFFF81662142 }
timestamp = 09:53:54.443945296, delta = +0.000019908, trace = /home/daniel/lttng-traces/krpso-20131119-095319/kernel, trace:hostname = sds-dut-vb, trace:domain = kernel, name = krpso_return, stream.packet.context = { cpu_id = 0 }, event.fields = { ip = 0xFFFFFFFF81176A70, parent_ip = 0xFFFFFFFF81662142 }
I knew the absolute address of whatever called sys_open, so I continue with this:
$ lttng enable-event -k krpso_parent --function 0xffffffff81662142 kernel event krpso_parent created in channel channel0
At which point the session manager just dies, with no message whatsoever.
If I instead do the equivalent symbol+offset command:
$ lttng enable-event -k krpso_parent --function sys_open+0x4EB6D2 k event k created in channel c Erreur du bus (core dumped)
Or this (just in case this is related to bug #633):
$ lttng enable-event -k krpso_parent --function sys_open+5158610 k event k created in channel c Erreur du bus (core dumped)
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