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Bug #926

closed

Kernel dynamic function/probe tracing does not work

Added by Philippe Proulx over 8 years ago. Updated over 8 years ago.

Status:
Resolved
Priority:
Normal
Target version:
Start date:
09/01/2015
Due date:
% Done:

100%

Estimated time:

Description

Using:

  • LTTng-tools master: b789735ec96305f2e14fc9b9c75406ca215ddabb
  • LTTng-modules master: f6da044fcd41afe52612b72376672912b2118ce4
  • Linux: Linux archeepp 4.1.4-1-ARCH #1 SMP PREEMPT Mon Aug 3 21:30:37 UTC 2015 x86_64 GNU/Linux

Dynamic function/probe tracing does not seem to work:

lttng create a
lttng enable-event -k --function do_open do_open
lttng enable-event -k --probe do_open do_open2
lttng enable-event -k --syscall open
lttng list a

do_open/do_open2 are not shown:

Tracing session a: [inactive]
    Trace path: /home/eepp/lttng-traces/a-20150901-185835

=== Domain: Kernel ===

Channels:
-------------
- channel0: [enabled]

    Attributes:
      overwrite mode: 0
      subbufers size: 262144
      number of subbufers: 4
      switch timer interval: 0
      read timer interval: 200000
      trace file count: 0
      trace file size (bytes): 0
      output: splice()

    Events:
      open (type:syscall) [enabled]

Let's trace:

lttng start
# ...
lttng stop

Now,

lttng view | grep wc -l

shows 566 events, where:

lttng view | grep do_open

none are do_open* events.

Actions #1

Updated by Mathieu Desnoyers over 8 years ago

  • Project changed from LTTng to LTTng-modules
  • Assignee set to Mathieu Desnoyers
  • Target version set to 2.7
Actions #2

Updated by Mathieu Desnoyers over 8 years ago

  • Status changed from New to Resolved
  • % Done changed from 0 to 100

Applied in changeset modules|commit:a0493bef1367458230b0319401f8533b0400cea2.

Actions #3

Updated by Mathieu Desnoyers over 8 years ago

For future reference: do_open exists, but is almost never executed. Use "do_sys_open" instead.

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