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Re: 3 bugs found.


David Smith wrote:
James Dickens wrote:
Here are 3 scripts, one line each, they each break the Systemtap one
is old, just needs to expand the current bug report.

Linux localhost.localdomain 2.6.17-1.2187_FC5 #1 Mon Sep 11 01:17:06
EDT 2006 i686 athlon i386 GNU/Linux

Since I've got a similar system (except mine isn't an athlon), I decided to take a look at these. See stuff below.


Latest cvs updates as of 2 hours ago.

Distro: Fedora FC5

Stack fault on the cpu. Halting the machine, This is x86 previously
only filed for x86_64

probe kernel.function("*") { print(".") }

To narrow it down a bit, this causes the same stack fault

probe kernel.function("*@kernel/*") { printf("here\n"); }

I've narrowed this one down. This only happens when probing 'atomic_notifier_call_chain'.


This one produces an oops, I can post the end of it, if nobudy else
can reproduce that has a serial console.

probe kernel.function("*@kernel/spinlock.c") { printf("."); }

I've reproduced this one with '_spin_unlock_irqrestore'. On the console I get:


BUG: spinlock lockup on CPU#0

With those two functions added to the blacklist (I'm not sure that is the right fix, I just want to get past those two functions), the following works correctly:

probe kernel.function("*@kernel/*") { printf("here\n"); }

Now your first probe (probing the entire kernel) still fails. I'm trying to narrow it down.

I've found it. If I add '_raw_spin_unlock' to the blacklist (along with 'atomic_notifier_call_chain' and '_spin_unlock_irqrestore'), then probing kernel.function("*") works fine for me on x86.


Note that once again I'm not sure that is the correct fix (adding it to the blacklist), I just wanted to get past it.

--
David Smith
dsmith@redhat.com
Red Hat, Inc.
http://www.redhat.com
256.217.0141 (direct)
256.837.0057 (fax)


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