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staprun -c deadlocks often
- From: "Richard W.M. Jones" <rjones at redhat dot com>
- To: systemtap at sourceware dot org
- Date: Fri, 17 Jun 2011 16:43:20 +0100
- Subject: staprun -c deadlocks often
systemtap-1.4-9.fc15.x86_64
kernel 2.6.38.7-30.fc15.x86_64
I'm not sure if I'm "doing it wrong", but it appears that the staprun -c
option deadlocks for me very frequently. Not always, but at least
more often than one time in two.
Here is what I'm doing (as root):
stap -p4 \
-e 'probe module("ext2").statement ("*@*.c:*") { printf ("%s\n", pp()); }'
[stap command prints the module name, used below]
staprun -o /tmp/stap -c /bin/ls /home/rjones/.systemtap/cache/44/stap_44fe38ee6f62656645948ce5d275d678_260427.ko
As I say, more often than half the time, instead of printing out a
directory listing, the staprun command will just hang. Note that the
filesystem I'm listing is not ext2, so I don't think the probes
themselves have anything to do with it.
When it hangs, a process listing shows:
13073 pts/4 Ss 0:00 \_ bash
17930 pts/4 S+ 0:00 | \_ sudo staprun -o /tmp/stap -c /bin/ls /home/rjones/.systemtap/cache/44/stap_44fe38ee6f62656645948ce5d275d678_260427.ko
17931 pts/4 Sl+ 0:00 | \_ /usr/libexec/systemtap/stapio -o /tmp/stap -c /bin/ls /home/rjones/.systemtap/cache/44/stap_44fe38ee6f62656645948ce5d275d678_260427.ko
17932 pts/4 S+ 0:00 | \_ /usr/libexec/systemtap/stapio -o /tmp/stap -c /bin/ls /home/rjones/.systemtap/cache/44/stap_44fe38ee6f62656645948ce5d275d678_260427.ko
Note that there is no staprun process, nor any /bin/ls, but two stapio
processes have been left around.
Any ideas? I had a look at the code in runtime/staprun/mainloop.c but
it just looks fiendishly complex ...
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
New in Fedora 11: Fedora Windows cross-compiler. Compile Windows
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