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Bug #687

closed

Crashing lttng-sessiond with enable-event --function

Added by Daniel U. Thibault over 8 years ago. Updated 4 months ago.

Status:
Invalid
Priority:
Low
Target version:
-
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)


Files

CrashLog.txt (20.6 KB) CrashLog.txt Crash log of lttng-sessiond Daniel U. Thibault, 11/19/2013 10:34 AM
sessiond.log (42.4 KB) sessiond.log Daniel U. Thibault, 02/25/2014 09:02 AM
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