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Warning for buildok/context_test.stp on utrace kernel
- From: Wenji Huang <wenji dot huang at oracle dot com>
- To: systemTAP <systemtap at sources dot redhat dot com>
- Date: Wed, 10 Feb 2010 17:42:34 +0800
- Subject: Warning for buildok/context_test.stp on utrace kernel
- Reply-to: wenji dot huang at oracle dot com
Hi,
There will be warning if we run the following test on
RHEL5, Fedora kernel or utrace kernel.
$ stap -p4 testsuite/buildok/context_test.stp
WARNING: "uprobe_get_pc"
[/tmp/staphrGioI/stap_0aef4ead3fec39f2dee30c60b1b684d2_8042.ko] undefined!
/home/wjhuang/.systemtap/cache/0a/stap_0aef4ead3fec39f2dee30c60b1b684d2_8042.ko
There reason is from print_ubacktrace() in probe.
In fact, if we run stap -ve 'probe begin(print_ubacktrace()){}' on
utrace kernel without loaded uprobes module. We can see the error
Error inserting module
'/tmp/stap0t5pyH/stap_5bd1a1d6b83ff84cfa8e7c67a402fa40_1153.ko': Unknown
symbol in module
since no symbol uprobe_get_pc can be resolved.
Yes, the test case is a little picky, but maybe we can
process it in a more graceful way.
BTW: there is no manual for print_ubacktrace, ubacktrace(), etc.
Regards,
Wenji